黑盒子出現錯誤訊息

ralfgn0429

	ERROR - java.lang.NullPointerException         at com.lineage.server.model.Instance.L1DollInstance.startDollSkill(lma:347)         at com.lineage.server.model.L1AttackPc.calcDamage(eaa:394)         at com.lineage.server.model.Instance.L1MonsterInstance.onAction(npa:744)         at com.lineage.server.clientpackets.C_Attack.start(hya:199)         at com.lineage.echo.PacketHandler.handlePacket(yya:12)         at com.lineage.echo.PacketHc.run(dcb:209)         at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)         at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)         at java.lang.Thread.run(Unknown Source) 請問有大大知道這個是甚麼原因嗎?謝謝