Chicken Chunks Crash

---- Minecraft Crash Report ----
// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 10/04/13 18:59
Description: Exception in server tick loop

java.lang.IllegalAccessError: tried to access field im.g from class codechicken.chunkloader.PlayerChunkViewerManager
    at codechicken.chunkloader.PlayerChunkViewerManager.calculateChunkChanges(PlayerChunkViewerManager.java:155)
    at codechicken.chunkloader.ChunkLoaderEventHandler.tickEnd(ChunkLoaderEventHandler.java:40)
    at cpw.mods.fml.common.SingleIntervalHandler.tickEnd(SingleIntervalHandler.java:22)
    at cpw.mods.fml.common.FMLCommonHandler.tickEnd(FMLCommonHandler.java:139)
    at cpw.mods.fml.common.FMLCommonHandler.onPostWorldTick(FMLCommonHandler.java:283)
    at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:689)
    at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:599)
    at bdz.q(IntegratedServer.java:170)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)
    at fy.run(SourceFile:849)