Something

java.lang.ClassCastException: net.sf.l2j.gameserver.model.L2MonsterInstance
        at net.sf.l2j.gameserver.handler.skillhandlers.Disablers.useSkill(Disabl
ers.java:93)
        at net.sf.l2j.gameserver.model.L2Character.callSkill(L2Character.java:44
92)
        at net.sf.l2j.gameserver.model.L2Character.onMagicUseTimer(L2Character.j
ava:4318)
        at net.sf.l2j.gameserver.model.L2Character$MagicUseTask.run(L2Character.
java:253)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
access$301(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source
)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)