Error

2013-11-09 20:54:59 [SEVERE] Error occurred while disabling DynamicDifficulty v1.0.0 (Is it up to date?)
java.util.ConcurrentModificationException
    at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
    at java.util.HashMap$ValueIterator.next(Unknown Source)
    at com.cjmcguire.bukkit.dynamic.DynamicDifficulty.saveAllPlayerInfo(DynamicDifficulty.java:219)
    at com.cjmcguire.bukkit.dynamic.DynamicDifficulty.onDisable(DynamicDifficulty.java:116)
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:219)
    at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:481)
    at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:401)
    at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:394)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.disablePlugins(CraftServer.java:283)
    at net.minecraft.server.v1_6_R3.MinecraftServer.stop(MinecraftServer.java:361)
    at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:457)
    at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)