issue when unloading Hb-ai for first time

2013-05-09 22:19:09 [INFO] [HerobrineAI] Disabling HerobrineAI v3.1.2
2013-05-09 22:19:09 [INFO] [HerobrineAI] Plugin disabled!
2013-05-09 22:19:09 [SEVERE] Exception in thread "MV-Inv Profile Write Thread"
2013-05-09 22:19:09 [SEVERE] java.lang.ExceptionInInitializerError
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.json.JSONArray.toJSONString(JSONArray.java:109)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.api.DataStrings.valueOf(DataStrings.java:687)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.api.share.PotionEffectSerializer.serialize(PotionEffectSerializer.java:19)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.api.share.PotionEffectSerializer.serialize(PotionEffectSerializer.java:10)
2013-05-09 22:19:09 [INFO] COMMAND: pm unload HerobrineAI
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.data.DefaultPlayerProfile.serialize(DefaultPlayerProfile.java:172)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData.processProfileWrite(FlatFilePlayerData.java:241)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData.access$000(FlatFilePlayerData.java:30)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.data.FlatFilePlayerData$FileWriteThread.run(FlatFilePlayerData.java:209)
2013-05-09 22:19:09 [SEVERE] Caused by: java.util.ConcurrentModificationException
2013-05-09 22:19:09 [SEVERE] 	at java.util.LinkedHashMap$LinkedHashIterator.nextEntry(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.util.LinkedHashMap$KeyIterator.next(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.JavaPluginLoader.getClassByName0(JavaPluginLoader.java:296)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:76)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.loadClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.loadClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.defineClass1(Native Method)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.defineClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.security.SecureClassLoader.defineClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.net.URLClassLoader.defineClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.net.URLClassLoader.access$100(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.net.URLClassLoader$1.run(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.net.URLClassLoader$1.run(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.security.AccessController.doPrivileged(Native Method)
2013-05-09 22:19:09 [SEVERE] 	at java.net.URLClassLoader.findClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.JavaPluginLoader.getClassByName0(JavaPluginLoader.java:300)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:76)
2013-05-09 22:19:09 [SEVERE] 	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.loadClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at java.lang.ClassLoader.loadClass(Unknown Source)
2013-05-09 22:19:09 [SEVERE] 	at com.onarandombox.multiverseinventories.util.json.JSONValue.<clinit>(JSONValue.java:53)
2013-05-09 22:19:09 [SEVERE] 	... 8 more