MInecraft 1.12 Adding New Block Error

Hello I was trying to program a mod for 1.12.2 because me and my friends are still playing on a old server that's running some mod that are only for 1.12.

I wanted to add my own stuff to it, but i keep running in to a problem when adding a new "basic" blocks

package com.DarkMod.BetterTools.Blocks;

import java.util.ArrayList;
import java.util.List;

import com.DarkMod.BetterTools.BetterTools;

import net.minecraft.block.Block;
import net.minecraft.block.material.Material;
import net.minecraft.creativetab.CreativeTabs;

public class BetterTools_Blocks {
	
	public static final List<Block> BLOCKS = new ArrayList<Block>();
	
	//Regular Blocks
	public static Block test_block;
	public static Block test_block2;
	
	public static void InitBlock() {
      	                                                  // ERROR vvvvvvvvvvvv
		test_block = RegisterBlock("test_block", new Block(Material.IRON), BetterTools.tab_bettertools);		
	}

	public static Block RegisterBlock(String blockName, Block block, CreativeTabs tabs) {		
		block.setUnlocalizedName(blockName);
		block.setRegistryName(blockName);
		block.setCreativeTab(tabs);
		
		BetterTools.logger.info("Blocks | " + block);
      
		BLOCKS.add(block);
		return block;
	}

}

When i register a new block using the Base class  Block(). my test block is set to Block{minecraft:air}

Resulting in the block not working  and returning the error

[01:27:20] [Client thread/ERROR] [FML]: Exception loading model for variant minecraft:air#inventory for item "minecraft:air", normal location exception: 
net.minecraftforge.client.model.ModelLoaderRegistry$LoaderException: Exception loading model minecraft:item/air with loader VanillaLoader.INSTANCE, skipping
	at net.minecraftforge.client.model.ModelLoaderRegistry.getModel(ModelLoaderRegistry.java:161) ~[ModelLoaderRegistry.class:?]
	at net.minecraftforge.client.model.ModelLoader.loadItemModels(ModelLoader.java:302) ~[ModelLoader.class:?]
	at net.minecraft.client.renderer.block.model.ModelBakery.loadVariantItemModels(ModelBakery.java:175) ~[ModelBakery.class:?]
	at net.minecraftforge.client.model.ModelLoader.setupModelRegistry(ModelLoader.java:151) ~[ModelLoader.class:?]
	at net.minecraft.client.renderer.block.model.ModelManager.onResourceManagerReload(ModelManager.java:28) [ModelManager.class:?]
	at net.minecraft.client.resources.SimpleReloadableResourceManager.registerReloadListener(SimpleReloadableResourceManager.java:121) [SimpleReloadableResourceManager.class:?]
	at net.minecraft.client.Minecraft.init(Minecraft.java:513) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:378) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_271]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_271]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_271]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_271]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_271]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_271]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_271]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_271]
	at net.minecraftforge.legacydev.Main.start(Main.java:86) [legacydev-0.2.3.1-fatjar.jar:0.2.3.1+4+372be23]
	at net.minecraftforge.legacydev.MainClient.main(MainClient.java:29) [legacydev-0.2.3.1-fatjar.jar:0.2.3.1+4+372be23]
Caused by: java.io.FileNotFoundException: minecraft:models/item/air.json
	at net.minecraft.client.resources.FallbackResourceManager.getResource(FallbackResourceManager.java:69) ~[FallbackResourceManager.class:?]
	at net.minecraft.client.resources.SimpleReloadableResourceManager.getResource(SimpleReloadableResourceManager.java:65) ~[SimpleReloadableResourceManager.class:?]
	at net.minecraft.client.renderer.block.model.ModelBakery.loadModel(ModelBakery.java:334) ~[ModelBakery.class:?]
	at net.minecraftforge.client.model.ModelLoader.access$1400(ModelLoader.java:115) ~[ModelLoader.class:?]
	at net.minecraftforge.client.model.ModelLoader$VanillaLoader.loadModel(ModelLoader.java:861) ~[ModelLoader$VanillaLoader.class:?]
	at net.minecraftforge.client.model.ModelLoaderRegistry.getModel(ModelLoaderRegistry.java:157) ~[ModelLoaderRegistry.class:?]
	... 20 more

Any idea what might be causing the problems?

If i need to post anything else to help let me know.