I have a problem that appear in my console and i dont know how to fix it. Can someone give me a hand? thanks a lot

Exception in thread "AISTPool-7" java.lang.NullPointerException
        at net.sf.l2j.gameserver.model.actor.instance.L2PcInstance.doDie(L2PcIns
tance.java:4122)
        at net.sf.l2j.gameserver.model.actor.status.PcStatus.reduceHp(PcStatus.j
ava:218)
        at net.sf.l2j.gameserver.model.actor.instance.L2PcInstance.reduceCurrent
Hp(L2PcInstance.java:9085)
        at net.sf.l2j.gameserver.model.actor.L2Character.reduceCurrentHp(L2Chara
cter.java:5683)
        at net.sf.l2j.gameserver.model.actor.L2Character.onHitTimer(L2Character.
java:4155)
        at net.sf.l2j.gameserver.model.actor.L2Character$HitTask.run(L2Character
.java:2150)
        at net.sf.l2j.gameserver.ThreadPoolManager$RunnableWrapper.run(ThreadPoo
lManager.java:85)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:47
1)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
access$201(ScheduledThreadPoolExecutor.java:178)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.
run(ScheduledThreadPoolExecutor.java:292)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.
java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor
.java:615)
        at java.lang.Thread.run(Thread.java:745)

Its caused by DeLevel = true. Old rev of aCis :P