Help Level Problem

Hello, i have a problem with experience,i have lvl 80 and 200%,when i kill a monster,i get deleveled.

This is a picture : http://imageshack.com/a/img843/9370/eb7pm.jpg

Also,

This is the error in gameserver console:

INFO [com.l2jfrozen.gameserver.model.L2Character] - 
java.lang.ClassCastException: com.l2jfrozen.gameserver.model.actor.instance.L2MonsterInstance cannot be cast to com.l2jfrozen.gameserver.model.actor.instance.L2PlayableInstance
   at com.l2jfrozen.gameserver.handler.skillhandlers.CpDam.useSkill(CpDam.java:48)
   at com.l2jfrozen.gameserver.model.L2Character.callSkill(L2Character.java:8158)
   at com.l2jfrozen.gameserver.model.actor.instance.L2PcInstance.callSkill(L2PcInstance.java:4682)
   at com.l2jfrozen.gameserver.model.L2Character.onMagicHitTimer(L2Character.java:7625)
   at com.l2jfrozen.gameserver.model.L2Character$MagicUseTask.run(L2Character.java:3050)
   at com.l2jfrozen.gameserver.thread.ThreadPoolManager$RunnableWrapper.run(ThreadPoolManager.java:433)
   at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
   at java.util.concurrent.FutureTask.run(Unknown Source)
   at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(Unknown Source)
   at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)