Error

[Server thread/ERROR] [FML]: A TileEntity type noahc3.abilitystones.tileentity.StonesChestTileEntity has throw an exception trying to write state. It will not persist. Report this to the mod author
java.lang.RuntimeException: class noahc3.abilitystones.tileentity.StonesChestTileEntity is missing a mapping! This is a bug!
	at net.minecraft.tileentity.TileEntity.writeToNBT(TileEntity.java:94) ~[TileEntity.class:?]
	at noahc3.abilitystones.tileentity.StonesChestTileEntity.writeToNBT(StonesChestTileEntity.java:159) ~[StonesChestTileEntity.class:?]
	at net.minecraft.world.chunk.storage.AnvilChunkLoader.writeChunkToNBT(AnvilChunkLoader.java:410) [AnvilChunkLoader.class:?]
	at net.minecraft.world.chunk.storage.AnvilChunkLoader.saveChunk(AnvilChunkLoader.java:193) [AnvilChunkLoader.class:?]
	at net.minecraft.world.gen.ChunkProviderServer.saveChunkData(ChunkProviderServer.java:266) [ChunkProviderServer.class:?]
	at net.minecraft.world.gen.ChunkProviderServer.saveChunks(ChunkProviderServer.java:332) [ChunkProviderServer.class:?]
	at net.minecraft.world.WorldServer.saveAllChunks(WorldServer.java:976) [WorldServer.class:?]
	at net.minecraft.server.MinecraftServer.saveAllWorlds(MinecraftServer.java:419) [MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:692) [MinecraftServer.class:?]
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:171) [IntegratedServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:540) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_45]