[22:20:11] [Server thread/ERROR]: Could not pass event PlayerDeathEvent to PrivateDeathMessage v1.9.2
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:294) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:501) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:486) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at org.bukkit.craftbukkit.v1_7_R3.event.CraftEventFactory.callPlayerDeathEvent(CraftEventFactory.java:370) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.EntityPlayer.die(EntityPlayer.java:373) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.EntityLiving.damageEntity(EntityLiving.java:732) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.EntityHuman.damageEntity(EntityHuman.java:746) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.EntityPlayer.damageEntity(EntityPlayer.java:452) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.EntityHuman.attack(EntityHuman.java:925) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.PlayerConnection.a(PlayerConnection.java:1106) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.PacketPlayInUseEntity.a(SourceFile:55) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.PacketPlayInUseEntity.handle(SourceFile:10) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.NetworkManager.a(NetworkManager.java:157) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.ServerConnection.c(SourceFile:134) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.MinecraftServer.v(MinecraftServer.java:667) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.DedicatedServer.v(DedicatedServer.java:260) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.MinecraftServer.u(MinecraftServer.java:558) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.MinecraftServer.run(MinecraftServer.java:469) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    at net.minecraft.server.v1_7_R3.ThreadServerApplication.run(SourceFile:628) [craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
Caused by: java.util.ConcurrentModificationException
    at java.util.ArrayList$Itr.checkForComodification(Unknown Source) ~[?:1.8.0]
    at java.util.ArrayList$Itr.next(Unknown Source) ~[?:1.8.0]
    at a4.privatedeath.Main.onKill(Main.java:162) ~[?:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0]
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:292) ~[craftbukkit.jar:git-Bukkit-1.7.9-R0.1-b3084jnks]
    ... 19 more
[22:20:19] [Server thread/INFO]: A3_Papers lost connection: Disconnected
[22:20:19] [Server thread/INFO]: A3_Papers left the game.