the error is here https://pastebin.com/vKiSRk1X

 

this is the GitHub https://github.com/Mystic4pheonix/witcherymod

You're not calling this method anywhere. The tile wasn't even registered, also you should probably update forge since that GameRegistry#registerTileEntity method was deprecated... you should use the one with ResourceLocation parameter instead of string... or just make the string be like this "modid:tilename"

fixed that new error https://pastebin.com/rzqSwGnH

 

[00:46:31] [main/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
    at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_171]
    at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_171]
    at net.minecraft.util.Util.runTask(Util.java:54) [Util.class:?]
    at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1176) [Minecraft.class:?]
    at net.minecraft.client.Minecraft.run(Minecraft.java:441) [Minecraft.class:?]
    at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_171]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_171]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_171]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_171]
    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_171]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_171]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_171]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_171]
    at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
    at GradleStart.main(GradleStart.java:25) [start/:?]
Caused by: java.lang.NullPointerException
    at team.mystic4phoenix.witchery.client.gui.GuiWitchOven.<init>(GuiWitchOven.java:23) ~[GuiWitchOven.class:?]
    at team.mystic4phoenix.witchery.client.gui.GuiHandler.getClientGuiElement(GuiHandler.java:48) ~[GuiHandler.class:?]
    at net.minecraftforge.fml.common.network.NetworkRegistry.getLocalGuiContainer(NetworkRegistry.java:279) ~[NetworkRegistry.class:?]
    at net.minecraftforge.fml.common.network.internal.FMLNetworkHandler.openGui(FMLNetworkHandler.java:111) ~[FMLNetworkHandler.class:?]
    at net.minecraft.entity.player.EntityPlayer.openGui(EntityPlayer.java:2809) ~[EntityPlayer.class:?]
    at net.minecraftforge.fml.common.network.internal.OpenGuiHandler.process(OpenGuiHandler.java:50) ~[OpenGuiHandler.class:?]
    at net.minecraftforge.fml.common.network.internal.OpenGuiHandler.lambda$channelRead0$0(OpenGuiHandler.java:43) ~[OpenGuiHandler.class:?]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_171]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_171]
    at net.minecraft.util.Util.runTask(Util.java:53) ~[Util.class:?]
    ... 15 more

this is one of the errors that keep pop up

where do I register guis

 

I would need more info you mean register them as a single you do it in your preInit

		NetworkRegistry.INSTANCE.registerGuiHandler(Main.instance, new GuiHandler());

Of course, you would need a GUIHandler

package com.mrf.infinityweapons.util.handlers;

import com.mrf.infinityweapons.container.Container_Lava_Compressor;
import com.mrf.infinityweapons.gui.GUI_Lava_Compressor;
import com.mrf.infinityweapons.tileentitys.TileEntity_Lava_Compressor;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;
import net.minecraftforge.fml.common.network.IGuiHandler;

public class GuiHandler implements IGuiHandler {

    public static final int GUINAMEHERE = 0;
    
    @Override
    public Object getServerGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
        if (ID == GUINAMEHERE) {
            return new CONTAINERCLASSHERE(player.inventory, (YourTileEntityHere) world.getTileEntity(new BlockPos(x, y, z)));
        }
        return null;
    }

    @Override
    public Object getClientGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
        if (ID == GUINAMEHERE) {
            return new GUICLASSHERE(player.inventory, (YourTileEntityHere) world.getTileEntity(new BlockPos(x, y, z)));
        }
        return null;
    }
    
}

Just fill in the blanks 

Hope this helped!