L2J Server

Hi I got gracia 2.1 and console is throwing this error:

Bad RequestBypassToServer:
java.lang.NullPointerException
at net.sf.l2j.gameserver.model.actor.instance.L2NpcInstance.makeSupportM
agic(L2NpcInstance.java:1756)
at net.sf.l2j.gameserver.model.actor.instance.L2NpcInstance.onBypassFeed
back(L2NpcInstance.java:998)
at net.sf.l2j.gameserver.network.clientpackets.RequestBypassToServer.run
Impl(RequestBypassToServer.java:120)
at net.sf.l2j.gameserver.network.clientpackets.L2GameClientPacket.run(L2
GameClientPacket.java:76)
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)



What does it means?
Tnx!

check the lines with error from L2PcInstance.