ZombieSurvival Error - VER 1.6

2012-07-22 19:59:25 [SEVERE] Could not pass event EntityDeathEvent to ZombieSurvival
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:304)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:460)
	at org.bukkit.craftbukkit.event.CraftEventFactory.callEntityDeathEvent(CraftEventFactory.java:299)
	at net.minecraft.server.EntityLiving.dropDeathLoot(EntityLiving.java:836)
	at net.minecraft.server.EntityLiving.die(EntityLiving.java:781)
	at net.minecraft.server.EntityLiving.damageEntity(EntityLiving.java:677)
	at net.minecraft.server.EntityMonster.damageEntity(EntityMonster.java:38)
	at net.minecraft.server.EntityHuman.attack(EntityHuman.java:750)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:998)
	at net.minecraft.server.Packet7UseEntity.handle(SourceFile:33)
	at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
	at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:567)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:459)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
	at com.bjornke.zombiesurvival.main.onZombieDeath(main.java:1653)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302)
	... 16 more