errors appear every time a command is typed!

Whenever my friend types a command this error appears in the console.


12.01 13:48:27 [Server] INFO Flashera was slain by Zombie
12.01 13:48:14 [Server] INFO ... 29 more
12.01 13:48:14 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
12.01 13:48:14 [Server] INFO at java.lang.reflect.Method.invoke(Unknown Source)
12.01 13:48:14 [Server] INFO at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
12.01 13:48:14 [Server] INFO at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
12.01 13:48:14 [Server] INFO at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
12.01 13:48:14 [Server] INFO at me.Mackerbaron.UC.Listener.onEntityExplode.onDamage(onEntityExplode.java:48)
12.01 13:48:14 [Server] INFO Caused by: java.lang.NullPointerException
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:580)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.WorldServer.tickEntities(WorldServer.java:445)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.World.tickEntities(World.java:1193)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.World.playerJoinedWorld(World.java:1315)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.WorldServer.entityJoinedWorld(WorldServer.java:548)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.World.entityJoinedWorld(World.java:1334)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityZombie.j_(EntityZombie.java:121)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityMonster.j_(EntityMonster.java:24)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityLiving.j_(EntityLiving.java:534)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityZombie.c(EntityZombie.java:108)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityMonster.c(EntityMonster.java:20)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityLiving.c(EntityLiving.java:1273)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityLiving.bl(EntityLiving.java:1476)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.PathfinderGoalSelector.a(PathfinderGoalSelector.java:104)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.PathfinderGoalMeleeAttack.e(PathfinderGoalMeleeAttack.java:83)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityMonster.m(EntityMonster.java:88)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityPlayer.damageEntity(EntityPlayer.java:308)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityHuman.damageEntity(EntityHuman.java:615)
12.01 13:48:14 [Server] INFO at net.minecraft.server.v1_4_6.EntityLiving.damageEntity(EntityLiving.java:686)
12.01 13:48:14 [Server] INFO at org.bukkit.craftbukkit.v1_4_6.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:391)
12.01 13:48:14 [Server] INFO at org.bukkit.craftbukkit.v1_4_6.event.CraftEventFactory.callEntityDamageEvent(CraftEventFactory.java:369)
12.01 13:48:14 [Server] INFO at org.bukkit.craftbukkit.v1_4_6.event.CraftEventFactory.callEvent(CraftEventFactory.java:81)
12.01 13:48:14 [Server] INFO at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
12.01 13:48:14 [Server] INFO at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
12.01 13:48:14 [Server] INFO at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
12.01 13:48:14 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
12.01 13:48:14 [Server] INFO org.bukkit.event.EventException
12.01 13:48:14 [Server] SEVERE Could not pass event EntityDamageByEntityEvent to UltimateCommands v1.0

 

i would recommend essentialsgroupmanager, sometimes plugins like those completely lock all commands when a single thing is wrong.

 

I've used groupmanager and it just repetitively crashed my server, so I use PermissionsEx

 

Are they using Ultimate arena when this occurs?

org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
I am getting this error in console after initiatizing /UA too