Ptweak error

2012-03-16 21:50:00 [WARNING] Could not properly handle event CHUNK_LOAD:
java.lang.IllegalAccessError: Synchronized code got accessed from another thread: lishid.orebfuscator.threading.OrebfuscatorThreadUpdate
    at org.bukkit.event.Listener.onChunkLoad(Listener:0)
    at sun.reflect.GeneratedMethodAccessor280.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:441)
    at net.minecraft.server.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:103)
    at org.bukkit.craftbukkit.CraftWorld.getChunkAt(CraftWorld.java:117)
    at org.bukkit.craftbukkit.CraftWorld.getBlockAt(CraftWorld.java:81)
    at org.bukkit.craftbukkit.block.CraftBlock.getRelative(CraftBlock.java:144)
    at org.bukkit.craftbukkit.block.CraftBlock.getRelative(CraftBlock.java:152)
    at org.bukkit.craftbukkit.block.CraftBlock.getRelative(CraftBlock.java:148)
    at lishid.orebfuscator.obfuscation.Calculations.GetAjacentBlocks(Calculations.java:87)
    at lishid.orebfuscator.obfuscation.Calculations.GetAjacentBlocks(Calculations.java:87)
    at lishid.orebfuscator.obfuscation.Calculations.UpdateBlocksNearby(Calculations.java:56)
    at lishid.orebfuscator.threading.OrebfuscatorThreadUpdate.run(OrebfuscatorThreadUpdate.java:80)
2012-03-16 21:50:00 [INFO] This error is logged only once: it could have occurred multiple times by now.