Crashing every time i open up custom crafting table GUI

---- Minecraft Crash Report ----
// I let you down. Sorry :(

Time: 8/22/19 8:47 PM
Description: Ticking player

java.lang.ArrayIndexOutOfBoundsException: 3
	at java.util.Arrays$ArrayList.get(Arrays.java:3841)
	at net.minecraft.util.NonNullList.get(NonNullList.java:51)
	at net.mcreator.nekomod.MCreatorMergeTable$TileEntityCustom.getStackInSlot(MCreatorMergeTable.java:176)
	at net.minecraft.inventory.Slot.getStack(Slot.java:81)
	at net.minecraft.inventory.Container.detectAndSendChanges(Container.java:97)
	at net.minecraft.entity.player.EntityPlayerMP.onUpdate(EntityPlayerMP.java:365)
	at net.minecraft.world.World.updateEntityWithOptionalForce(World.java:2171)
	at net.minecraft.world.WorldServer.updateEntityWithOptionalForce(WorldServer.java:871)
	at net.minecraft.world.World.updateEntity(World.java:2130)
	at net.minecraft.world.WorldServer.tickPlayers(WorldServer.java:672)
	at net.minecraft.world.World.updateEntities(World.java:1906)
	at net.minecraft.world.WorldServer.updateEntities(WorldServer.java:643)
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:842)
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:743)
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:592)
	at java.lang.Thread.run(Thread.java:748)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Server thread
Stacktrace:
	at java.util.Arrays$ArrayList.get(Arrays.java:3841)
	at net.minecraft.util.NonNullList.get(NonNullList.java:51)
	at net.mcreator.nekomod.MCreatorMergeTable$TileEntityCustom.getStackInSlot(MCreatorMergeTable.java:176)
	at net.minecraft.inventory.Slot.getStack(Slot.java:81)
	at net.minecraft.inventory.Container.detectAndSendChanges(Container.java:97)
	at net.minecraft.entity.player.EntityPlayerMP.onUpdate(EntityPlayerMP.java:365)
	at net.minecraft.world.World.updateEntityWithOptionalForce(World.java:2171)
	at net.minecraft.world.WorldServer.updateEntityWithOptionalForce(WorldServer.java:871)
	at net.minecraft.world.World.updateEntity(World.java:2130)

-- Player being ticked --
Details:
	Entity Type: null (net.minecraft.entity.player.EntityPlayerMP)
	Entity ID: 156
	Entity Name: Player953
	Entity's Exact location: 262.25, 72.00, 74.67
	Entity's Block location: World: (262,72,74), Chunk: (at 6,4,10 in 16,4; contains blocks 256,0,64 to 271,255,79), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0.00, -0.08, 0.00
	Entity's Passengers: []
	Entity's Vehicle: ~~ERROR~~ NullPointerException: null
Stacktrace:
	at net.minecraft.world.WorldServer.tickPlayers(WorldServer.java:672)
	at net.minecraft.world.World.updateEntities(World.java:1906)
	at net.minecraft.world.WorldServer.updateEntities(WorldServer.java:643)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [EntityPlayerMP['Player953'/156, l='New World', x=262.25, y=72.00, z=74.67]]
	Chunk stats: ServerChunkCache: 272 Drop: 0
	Level seed: 8294375057556659278
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (224,64,72), Chunk: (at 0,4,8 in 14,4; contains blocks 224,0,64 to 239,255,79), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 6748 game time, 6748 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 14187 (now: false), thunder time: 88713 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:842)
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:743)
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:592)
	at java.lang.Thread.run(Thread.java:748)

-- System Details --
Details:
	Minecraft Version: 1.12.2
	Operating System: Windows 10 (amd64) version 10.0
	Java Version: 1.8.0_212, BellSoft
	Java VM Version: LibericaJDK 64-Bit Server VM (mixed mode), 
	Memory: 769734888 bytes (734 MB) / 940572672 bytes (897 MB) up to 3801088000 bytes (3625 MB)
	JVM Flags: 0 total; 
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	FML: MCP 9.42 Powered by Forge 14.23.5.2768 5 mods loaded, 5 mods active
	States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored

	| State     | ID        | Version      | Source                           | Signature |
	|:--------- |:--------- |:------------ |:-------------------------------- |:--------- |
	| UCHIJAAAA | minecraft | 1.12.2       | minecraft.jar                    | None      |
	| UCHIJAAAA | mcp       | 9.42         | minecraft.jar                    | None      |
	| UCHIJAAAA | FML       | 8.0.99.99    | forgeSrc-1.12.2-14.23.5.2768.jar | None      |
	| UCHIJAAAA | forge     | 14.23.5.2768 | forgeSrc-1.12.2-14.23.5.2768.jar | None      |
	| UCHIJAAAA | nekomod   | 1.0.0        | modid-1.0.jar                    | None      |

	Loaded coremods (and transformers): 
	GL info: ~~ERROR~~ RuntimeException: No OpenGL context found in the current thread.
	Profiler Position: N/A (disabled)
	Player Count: 1 / 8; [EntityPlayerMP['Player953'/156, l='New World', x=262.25, y=72.00, z=74.67]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Definitely; Client brand changed to 'fml,forge'

What does this mean and how do i fix it? please help