error log, need help

[Slind]

hey guys,

im getting this error for every loaded chunk in the forgemodloader-server-1.log

[ForgeModLoader] A TileEntity type any at world,-214,65,287 has throw an exception trying to write state. It will not persist. Report this to the mod author
java.lang.RuntimeException: class any is missing a mapping! This is a bug!
    at any.b(TileEntity.java:110)
    at aam.a(AnvilChunkLoader.java:389)
    at aam.a(AnvilChunkLoader.java:189)
    at im.b(ChunkProviderServer.java:313)
    at im.a(ChunkProviderServer.java:390)
    at in.a(WorldServer.java:1086)
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:621)
    at net.minecraft.server.MinecraftServer.k(MinecraftServer.java:660)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:799)
    at fy.run(ThreadMinecraftServer.java:16)

Can u help me to understand it ?