Error Logs

[11:14:44 ERROR]: Could not pass event EntityDeathEvent to HOLOPopup v1.0
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:320) ~[spigot.jar:git-Spigot-1314]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62) ~[spigot.jar:git-Spigot-1314]
        at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredLi
stener.java:30) ~[spigot.jar:git-Spigot-1314]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:482) [spigot.jar:git-Spigot-1314]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:467) [spigot.jar:git-Spigot-1314]
        at org.bukkit.craftbukkit.v1_7_R1.event.CraftEventFactory.callEntityDeat
hEvent(CraftEventFactory.java:349) [spigot.jar:git-Spigot-1314]
        at org.bukkit.craftbukkit.v1_7_R1.event.CraftEventFactory.callEntityDeat
hEvent(CraftEventFactory.java:342) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityLiving.die(EntityLiving.java:800)
[spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityLiving.damageEntity(EntityLiving.j
ava:739) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityMonster.damageEntity(EntityMonster
.java:47) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityZombie.damageEntity(EntityZombie.j
ava:156) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityIronGolem.m(EntityIronGolem.java:1
11) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.PathfinderGoalMeleeAttack.e(PathfinderGo
alMeleeAttack.java:100) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.PathfinderGoalSelector.a(PathfinderGoalS
elector.java:108) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityInsentient.bn(EntityInsentient.jav
a:433) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityLiving.e(EntityLiving.java:1443) [
spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityInsentient.e(EntityInsentient.java
:306) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityIronGolem.e(EntityIronGolem.java:7
3) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityLiving.h(EntityLiving.java:1306) [
spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.EntityInsentient.h(EntityInsentient.java
:150) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.World.entityJoinedWorld(World.java:1472)
 [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.World.playerJoinedWorld(World.java:1448)
 [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.World.tickEntities(World.java:1317) [spi
got.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.WorldServer.tickEntities(WorldServer.jav
a:514) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:6
71) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:2
73) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:5
60) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java
:467) [spigot.jar:git-Spigot-1314]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:6
17) [spigot.jar:git-Spigot-1314]
Caused by: java.lang.NullPointerException
        at me.ccrama.HOLOPopup.Main.killAnimals(Main.java:63) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0
_51]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0
_51]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1
.7.0_51]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_51]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:318) ~[spigot.jar:git-Spigot-1314]
        ... 28 more