java.lang.NullPointerException: Exception ticking world
    at codechicken.lib.world.WorldExtension.unloadChunk(WorldExtension.java:52)
    at codechicken.lib.world.WorldExtensionManager$WorldExtensionEventHandler.onChunkUnLoad(WorldExtensionManager.java:67)
    at cpw.mods.fml.common.eventhandler.ASMEventHandler_553_WorldExtensionEventHandler_onChunkUnLoad_Unload.invoke(.dynamic)
    at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54)
    at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140)
    at net.minecraft.world.chunk.Chunk.func_76623_d(Chunk.java:941)
    at net.minecraft.world.gen.ChunkProviderServer.func_73156_b(ChunkProviderServer.java:342)
    at net.minecraft.world.WorldServer.func_72835_b(WorldServer.java:165)
    at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:625)
    at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:334)
    at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)