java.lang.NullPointerException
at net.sf.l2j.gameserver.model.L2Attackable.removeKnownObject(L2Attackable.java:264)
at net.sf.l2j.gameserver.model.L2MonsterInstance.removeKnownObject(L2MonsterInstance.java:122)
at net.sf.l2j.gameserver.model.L2World.removeVisibleObject(L2World.java:455)
at net.sf.l2j.gameserver.model.L2Object.decayMe(L2Object.java:425)
at net.sf.l2j.gameserver.model.L2Character.onDecay(L2Character.java:713)
at net.sf.l2j.gameserver.model.L2NpcInstance.onDecay(L2NpcInstance.java:950)
at net.sf.l2j.gameserver.model.L2Character$DecayTask.run(L2Character.java:393)
at java.util.concurrent.Executors$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)