Tile entity not acting as it should and throws error

[Yagoki]

I'm trying to create a tile entity which pulls nearby entities towards it. looking at other peoples code for tile entities I put together the following class (how the class currently affects the player is just to see if it's working, [also i changed some stuff without cleaning my code to see whether it was just variables being too small for me to notice the effect])

http://gw.minecraftforge.net/84qY

 

The block class is here: http://gw.minecraftforge.net/hbiC

 

when i run the game it throws the following error:

2013-02-24 17:48:38 [sEVERE] [ForgeModLoader] A TileEntity type yagoki.mods.mtech.blocks.tile.TileEntityAttractor has throw an exception trying to write state. It will not persist. Report this to the mod author
java.lang.RuntimeException: class yagoki.mods.mtech.blocks.tile.TileEntityAttractor is missing a mapping! This is a bug!
at net.minecraft.tileentity.TileEntity.writeToNBT(TileEntity.java:107)
at net.minecraft.world.chunk.storage.AnvilChunkLoader.writeChunkToNBT(AnvilChunkLoader.java:311)
at net.minecraft.world.chunk.storage.AnvilChunkLoader.saveChunk(AnvilChunkLoader.java:127)
at net.minecraft.world.gen.ChunkProviderServer.safeSaveChunk(ChunkProviderServer.java:232)
at net.minecraft.world.gen.ChunkProviderServer.saveChunks(ChunkProviderServer.java:284)
at net.minecraft.world.WorldServer.saveAllChunks(WorldServer.java:844)
at net.minecraft.server.MinecraftServer.saveAllWorlds(MinecraftServer.java:373)
at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
at net.minecraft.server.ThreadMinecraftServer.run(ThreadMinecraftServer.java:16)

 

can someone tell me how to resolve this, as I've not (as far as I can tell) done anything different to the classes I learnt form which all, supposedly, work fine.

[Yagoki]

thanks, it no longer throws the error but the update entity method isn't getting called

[Yagoki]

ok that was a bit of a derp moment, moved it there earlier without thinking to make the code look neater.

Thanks for pointing that out.