Inventory Not Saving Blocks [SOlVED]

I have a custom inventory that stores blocks and items during the game. However, when I save and quit and come back on, all of the blocks in the inventory were gone! Any help appreciated.

 public class EventCustomInventory implements IExtendedEntityProperties,
	IInventory {

private ItemStack[] inv;

public ItemStack[] armorInventory = new ItemStack[4];

/** The index of the currently held item (0-. */
public int currentItem = 0;
@SideOnly(Side.CLIENT)
/** The current ItemStack. */
private ItemStack currentItemStack;

/** The player whose inventory this is. */
public EntityPlayer player;
private ItemStack itemStack;

public EventCustomInventory() {
	inv = new ItemStack[48];
}

@Override
public void saveNBTData(NBTTagCompound compound) {

	NBTTagList itemList = new NBTTagList();
	for (int i = 0; i < inv.length; i++) {
		ItemStack stack = inv[i];
		if (stack != null) {
			NBTTagCompound tag = new NBTTagCompound();
			tag.setByte("Slot", (byte) i);
			stack.writeToNBT(tag);
			itemList.appendTag(tag);
		}
	}
	compound.setTag("Inventory", itemList);

}

@Override
public void loadNBTData(NBTTagCompound compound) {

	NBTTagList tagList = compound.getTagList("Inventory");
	for (int i = 0; i < tagList.tagCount(); i++) {
		NBTTagCompound tag = (NBTTagCompound) tagList.tagAt(i);
		byte slot = tag.getByte("Slot");
		if (slot >= 0 && slot < inv.length) {
			inv[slot] = ItemStack.loadItemStackFromNBT(tag);
		}
	}

}

@Override
public void init(Entity entity, World world) {

}

/**
 * Set true whenever the inventory changes. Nothing sets it false so you
 * will have to write your own code to check it and reset the value.
 */
public boolean inventoryChanged = false;

/**
 * Returns the item stack currently held by the player.
 */
public ItemStack getCurrentItem() {
	return this.currentItem < 9 && this.currentItem >= 0 ? this.inv[this.currentItem]
			: null;
}

/**
 * Get the size of the player hotbar inventory
 */
public static int getHotbarSize() {
	return 9;
}

/**
 * Returns a slot index in main inventory containing a specific itemID
 */
private int getInventorySlotContainItem(int par1) {
	for (int j = 0; j < this.inv.length; ++j) {
		if (this.inv[j] != null && this.inv[j].itemID == par1) {
			return j;
		}
	}

	return -1;
}

@SideOnly(Side.CLIENT)
private int getInventorySlotContainItemAndDamage(int par1, int par2) {
	for (int k = 0; k < this.inv.length; ++k) {
		if (this.inv[k] != null && this.inv[k].itemID == par1
				&& this.inv[k].getItemDamage() == par2) {
			return k;
		}
	}

	return -1;
}

/**
 * stores an itemstack in the users inventory
 */
private int storeItemStack(ItemStack par1ItemStack) {
	for (int i = 0; i < this.inv.length; ++i) {
		if (this.inv[i] != null
				&& this.inv[i].itemID == par1ItemStack.itemID
				&& this.inv[i].isStackable()
				&& this.inv[i].stackSize < this.inv[i].getMaxStackSize()
				&& this.inv[i].stackSize < this.getInventoryStackLimit()
				&& (!this.inv[i].getHasSubtypes() || this.inv[i]
						.getItemDamage() == par1ItemStack.getItemDamage())
				&& ItemStack.areItemStackTagsEqual(this.inv[i],
						par1ItemStack)) {
			return i;
		}
	}

	return -1;
}

/**
 * Returns the first item stack that is empty.
 */
public int getFirstEmptyStack() {
	for (int i = 0; i < this.inv.length; ++i) {
		if (this.inv[i] == null) {
			return i;
		}
	}

	return -1;
}

@SideOnly(Side.CLIENT)
/**
 * Sets a specific itemID as the current item being held (only if it exists on the hotbar)
 */
public void setCurrentItem(int par1, int par2, boolean par3, boolean par4) {
	boolean flag2 = true;
	this.currentItemStack = this.getCurrentItem();
	int k;

	if (par3) {
		k = this.getInventorySlotContainItemAndDamage(par1, par2);
	} else {
		k = this.getInventorySlotContainItem(par1);
	}

	if (k >= 0 && k < 9) {
		this.currentItem = k;
	} else {
		if (par4 && par1 > 0) {
			int l = this.getFirstEmptyStack();

			if (l >= 0 && l < 9) {
				this.currentItem = l;
			}

			this.func_70439_a(Item.itemsList[par1], par2);
		}
	}
}

@SideOnly(Side.CLIENT)
/**
 * Switch the current item to the next one or the previous one
 */
public void changeCurrentItem(int par1) {
	if (par1 > 0) {
		par1 = 1;
	}

	if (par1 < 0) {
		par1 = -1;
	}

	for (this.currentItem -= par1; this.currentItem < 0; this.currentItem += 9) {
		;
	}

	while (this.currentItem >= 9) {
		this.currentItem -= 9;
	}
}

/**
 * Clear this player's inventory, using the specified ID and metadata as
 * filters or -1 for no filter.
 */
public int clearInventory(int par1, int par2) {
	int k = 0;
	int l;
	ItemStack itemstack;

	for (l = 0; l < this.inv.length; ++l) {
		itemstack = this.inv[l];

		if (itemstack != null && (par1 <= -1 || itemstack.itemID == par1)
				&& (par2 <= -1 || itemstack.getItemDamage() == par2)) {
			k += itemstack.stackSize;
			this.inv[l] = null;
		}
	}

	for (l = 0; l < this.armorInventory.length; ++l) {
		itemstack = this.armorInventory[l];

		if (itemstack != null && (par1 <= -1 || itemstack.itemID == par1)
				&& (par2 <= -1 || itemstack.getItemDamage() == par2)) {
			k += itemstack.stackSize;
			this.armorInventory[l] = null;
		}
	}

	return k;
}

@SideOnly(Side.CLIENT)
public void func_70439_a(Item par1Item, int par2) {
	if (par1Item != null) {
		int j = this.getInventorySlotContainItemAndDamage(par1Item.itemID,
				par2);

		if (j >= 0) {
			this.inv[j] = this.inv[this.currentItem];
		}

		if (this.currentItemStack != null
				&& this.currentItemStack.isItemEnchantable()
				&& this.getInventorySlotContainItemAndDamage(
						this.currentItemStack.itemID,
						this.currentItemStack.getItemDamageForDisplay()) == this.currentItem) {
			return;
		}

		this.inv[this.currentItem] = new ItemStack(
				Item.itemsList[par1Item.itemID], 1, par2);
	}
}

/**
 * This function stores as many items of an ItemStack as possible in a
 * matching slot and returns the quantity of left over items.
 */
private int storePartialItemStack(ItemStack par1ItemStack) {
	int i = par1ItemStack.itemID;
	int j = par1ItemStack.stackSize;
	int k;

	if (par1ItemStack.getMaxStackSize() == 1) {
		k = this.getFirstEmptyStack();

		if (k < 0) {
			return j;
		} else {
			if (this.inv[k] == null) {
				this.inv[k] = ItemStack.copyItemStack(par1ItemStack);
			}

			return 0;
		}
	} else {
		k = this.storeItemStack(par1ItemStack);

		if (k < 0) {
			k = this.getFirstEmptyStack();
		}

		if (k < 0) {
			return j;
		} else {
			if (this.inv[k] == null) {
				this.inv[k] = new ItemStack(i, 0,
						par1ItemStack.getItemDamage());

				if (par1ItemStack.hasTagCompound()) {
					this.inv[k]
							.setTagCompound((NBTTagCompound) par1ItemStack
									.getTagCompound().copy());
				}
			}

			int l = j;

			if (j > this.inv[k].getMaxStackSize() - this.inv[k].stackSize) {
				l = this.inv[k].getMaxStackSize() - this.inv[k].stackSize;
			}

			if (l > this.getInventoryStackLimit() - this.inv[k].stackSize) {
				l = this.getInventoryStackLimit() - this.inv[k].stackSize;
			}

			if (l == 0) {
				return j;
			} else {
				j -= l;
				this.inv[k].stackSize += l;
				this.inv[k].animationsToGo = 5;
				return j;
			}
		}
	}
}

/**
 * Decrement the number of animations remaining. Only called on client side.
 * This is used to handle the animation of receiving a block.
 */
public void decrementAnimations() {
	for (int i = 0; i < this.inv.length; ++i) {
		if (this.inv[i] != null) {
			this.inv[i].updateAnimation(this.player.worldObj, this.player,
					i, this.currentItem == i);
		}
	}

	for (int i = 0; i < this.armorInventory.length; i++) {
		if (this.armorInventory[i] != null) {
			this.armorInventory[i].getItem().onArmorTickUpdate(
					this.player.worldObj, this.player,
					this.armorInventory[i]);
		}
	}
}

/**
 * removed one item of specified itemID from inventory (if it is in a stack,
 * the stack size will reduce with 1)
 */
public boolean consumeInventoryItem(int par1) {
	int j = this.getInventorySlotContainItem(par1);

	if (j < 0) {
		return false;
	} else {
		if (--this.inv[j].stackSize <= 0) {
			this.inv[j] = null;
		}

		return true;
	}
}

/**
 * Get if a specifiied item id is inside the inventory.
 */
public boolean hasItem(int par1) {
	int j = this.getInventorySlotContainItem(par1);
	return j >= 0;
}

/**
 * Adds the item stack to the inventory, returns false if it is impossible.
 */
public boolean addItemStackToInventory(ItemStack par1ItemStack) {
	if (par1ItemStack == null) {
		return false;
	} else {
		try {
			int i;

			if (par1ItemStack.isItemDamaged()) {
				i = this.getFirstEmptyStack();

				if (i >= 0) {
					this.inv[i] = ItemStack.copyItemStack(par1ItemStack);
					this.inv[i].animationsToGo = 5;
					par1ItemStack.stackSize = 0;
					return true;
				} else {
					return false;
				}
			} else {
				do {
					i = par1ItemStack.stackSize;
					par1ItemStack.stackSize = this
							.storePartialItemStack(par1ItemStack);
				} while (par1ItemStack.stackSize > 0
						&& par1ItemStack.stackSize < i);

			}
			return par1ItemStack.stackSize < i;

		} catch (Throwable throwable) {
			CrashReport crashreport = CrashReport.makeCrashReport(
					throwable, "Adding item to inventory");
			CrashReportCategory crashreportcategory = crashreport
					.makeCategory("Item being added");
			crashreportcategory.addCrashSection("Item ID",
					Integer.valueOf(par1ItemStack.itemID));
			crashreportcategory.addCrashSection("Item data",
					Integer.valueOf(par1ItemStack.getItemDamage()));
			throw new ReportedException(crashreport);
		}
	}
}

/**
 * Removes from an inventory slot (first arg) up to a specified number
 * (second arg) of items and returns them in a new stack.
 */
public ItemStack decrStackSize(int par1, int par2) {
	ItemStack[] aitemstack = this.inv;

	if (par1 >= this.inv.length) {
		aitemstack = this.armorInventory;
		par1 -= this.inv.length;
	}

	if (aitemstack[par1] != null) {
		ItemStack itemstack;

		if (aitemstack[par1].stackSize <= par2) {
			itemstack = aitemstack[par1];
			aitemstack[par1] = null;
			return itemstack;
		} else {
			itemstack = aitemstack[par1].splitStack(par2);

			if (aitemstack[par1].stackSize == 0) {
				aitemstack[par1] = null;
			}

			return itemstack;
		}
	} else {
		return null;
	}
}

/**
 * When some containers are closed they call this on each slot, then drop
 * whatever it returns as an EntityItem - like when you close a workbench
 * GUI.
 */
public ItemStack getStackInSlotOnClosing(int par1) {
	ItemStack[] aitemstack = this.inv;

	if (par1 >= this.inv.length) {
		aitemstack = this.armorInventory;
		par1 -= this.inv.length;
	}

	if (aitemstack[par1] != null) {
		ItemStack itemstack = aitemstack[par1];
		aitemstack[par1] = null;
		return itemstack;
	} else {
		return null;
	}
}

/**
 * Sets the given item stack to the specified slot in the inventory (can be
 * crafting or armor sections).
 */
public void setInventorySlotContents(int par1, ItemStack par2ItemStack) {
	ItemStack[] aitemstack = this.inv;

	if (par1 >= aitemstack.length) {
		par1 -= aitemstack.length;
		aitemstack = this.armorInventory;
	}

	aitemstack[par1] = par2ItemStack;
}

/**
 * Gets the strength of the current item (tool) against the specified block,
 * 1.0f if not holding anything.
 */
public float getStrVsBlock(Block par1Block) {
	float f = 1.0F;

	if (this.inv[this.currentItem] != null) {
		f *= this.inv[this.currentItem].getStrVsBlock(par1Block);
	}

	return f;
}

/**
 * Returns the number of slots in the inventory.
 */
public int getSizeInventory() {
	return this.inv.length;
}

/**
 * Returns the stack in slot i
 */
public ItemStack getStackInSlot(int par1) {
	ItemStack[] aitemstack = this.inv;

	if (par1 >= aitemstack.length) {
		par1 -= aitemstack.length;
		aitemstack = this.armorInventory;
	}

	return aitemstack[par1];
}

/**
 * Returns the name of the inventory.
 */
public String getInvName() {
	return "CustomInventory";
}

/**
 * If this returns false, the inventory name will be used as an unlocalized
 * name, and translated into the player's language. Otherwise it will be
 * used directly.
 */
public boolean isInvNameLocalized() {
	return false;
}

/**
 * Returns the maximum stack size for a inventory slot. Seems to always be
 * 64, possibly will be extended. *Isn't this more of a set than a get?*
 */
public int getInventoryStackLimit() {
	return 64;
}

/**
 * Return damage vs an entity done by the current held weapon, or 1 if
 * nothing is held
 */
public int getDamageVsEntity(Entity par1Entity) {
	ItemStack itemstack = this.getStackInSlot(this.currentItem);
	return itemstack != null ? itemstack.getDamageVsEntity(par1Entity) : 1;
}

/**
 * Returns whether the current item (tool) can harvest from the specified
 * block (actually get a result).
 */
public boolean canHarvestBlock(Block par1Block) {
	if (par1Block.blockMaterial.isToolNotRequired()) {
		return true;
	} else {
		ItemStack itemstack = this.getStackInSlot(this.currentItem);
		return itemstack != null ? itemstack.canHarvestBlock(par1Block)
				: false;
	}
}

/**
 * returns a player armor item (as itemstack) contained in specified armor
 * slot.
 */
public ItemStack armorItemInSlot(int par1) {
	return this.armorInventory[par1];
}

/**
 * Based on the damage values and maximum damage values of each armor item,
 * returns the current armor value.
 */
public int getTotalArmorValue() {
	int i = 0;

	for (int j = 0; j < this.armorInventory.length; ++j) {
		if (this.armorInventory[j] != null
				&& this.armorInventory[j].getItem() instanceof ItemArmor) {
			int k = ((ItemArmor) this.armorInventory[j].getItem()).damageReduceAmount;
			i += k;
		}
	}

	return i;
}

/**
 * Damages armor in each slot by the specified amount.
 */
public void damageArmor(int par1) {
	par1 /= 4;

	if (par1 < 1) {
		par1 = 1;
	}

	for (int j = 0; j < this.armorInventory.length; ++j) {
		if (this.armorInventory[j] != null
				&& this.armorInventory[j].getItem() instanceof ItemArmor) {
			this.armorInventory[j].damageItem(par1, this.player);

			if (this.armorInventory[j].stackSize == 0) {
				this.armorInventory[j] = null;
			}
		}
	}
}

/**
 * Drop all armor and main inventory items.
 */
public void dropAllItems() {
	int i;

	for (i = 0; i < this.inv.length; ++i) {
		if (this.inv[i] != null) {
			this.player.dropPlayerItemWithRandomChoice(this.inv[i], true);
			this.inv[i] = null;
		}
	}

	for (i = 0; i < this.armorInventory.length; ++i) {
		if (this.armorInventory[i] != null) {
			this.player.dropPlayerItemWithRandomChoice(
					this.armorInventory[i], true);
			this.armorInventory[i] = null;
		}
	}
}

/**
 * Called when an the contents of an Inventory change, usually
 */
public void onInventoryChanged() {
	this.inventoryChanged = true;
}

public void setItemStack(ItemStack par1ItemStack) {
	this.itemStack = par1ItemStack;
}

public ItemStack getItemStack() {
	return this.itemStack;
}

/**
 * Do not make give this method the name canInteractWith because it clashes
 * with Container
 */
public boolean isUseableByPlayer(EntityPlayer par1EntityPlayer) {
	return this.player.isDead ? false : par1EntityPlayer
			.getDistanceSqToEntity(this.player) <= 64.0D;
}

/**
 * Returns true if the specified ItemStack exists in the inventory.
 */
public boolean hasItemStack(ItemStack par1ItemStack) {
	int i;

	for (i = 0; i < this.armorInventory.length; ++i) {
		if (this.armorInventory[i] != null
				&& this.armorInventory[i].isItemEqual(par1ItemStack)) {
			return true;
		}
	}

	for (i = 0; i < this.inv.length; ++i) {
		if (this.inv[i] != null && this.inv[i].isItemEqual(par1ItemStack)) {
			return true;
		}
	}

	return false;
}

public void openChest() {
}

public void closeChest() {
}

/**
 * Returns true if automation is allowed to insert the given stack (ignoring
 * stack size) into the given slot.
 */
public boolean isStackValidForSlot(int par1, ItemStack par2ItemStack) {
	return true;
}

/**
 * Copy the ItemStack contents from another InventoryPlayer instance
 */
public void copyInventory(EventCustomInventory par1InventoryPlayer) {
	int i;

	for (i = 0; i < this.inv.length; ++i) {
		this.inv[i] = ItemStack.copyItemStack(par1InventoryPlayer.inv[i]);
	}

	for (i = 0; i < this.armorInventory.length; ++i) {
		this.armorInventory[i] = ItemStack
				.copyItemStack(par1InventoryPlayer.armorInventory[i]);
	}

	this.currentItem = par1InventoryPlayer.currentItem;
}

}

Edit: Found the Solution. The NBT tag names should be changed so they arent those of the vanilla inventory.