Hello, server keeps crashing or dcing, help me please?

Code:
java.lang.NullPointerException

     at server.model.players.PlayerAssistant.applyDead(Player
Assistant.java:1786)

      at server.model.players.Client.process(Client.java:809)

     at server.model.players.PlayerHandler.process(PlayerHand
ler.java:177)

      at server.Server.main(Server.java:176)

java.lang.ArrayIndexOutOfBound***ception: -12

     at server.clip.region.ByteStream.getUByte(ByteStream.jav
a:41)

     at server.clip.region.ByteStream.getLong(ByteStream.java
:64)

     at server.clip.region.MemoryArchive.get(MemoryArchive.ja
va:22)

      at server.clip.region.ObjectDef.getObjectDef(ObjectDef.j
ava:16)

     at server.clip.region.Region.addObject(Region.java:188)

     at server.model.players.PlayerAssistant.checkObjectSpawn
(PlayerAssistant.java:1487)

      at server.world.ObjectManager.loadCustomSpawns(ObjectMan
ager.java:195)

     at server.world.ObjectManager.loadObjects(ObjectManager.
java:103)

      at server.model.players.packets.ChangeRegions.processPac
ket(ChangeRegions.java:16)

      at server.model.players.PacketHandler.processPacket(Pack
etHandler.java:142)

     at server.model.players.Client.processQueuedPackets(Clie
nt.java:1150)

      at server.model.players.PlayerHandler.process(PlayerHand
ler.java:176)

      at server.Server.main(Server.java:176)

 java.lang.NullPointerException

      at server.model.players.PlayerAssistant.applyDead(Player
Assistant.java:1786)

      at server.model.players.Client.process(Client.java:809)

      at server.model.players.PlayerHandler.process(PlayerHand
ler.java:177)

      at server.Server.main(Server.java:176)