[SEVERE] Could not pass event InventoryCloseEvent to EchoPet v2.0.6
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30)
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:478)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:463)
	at org.bukkit.craftbukkit.v1_6_R2.event.CraftEventFactory.handleInventoryCloseEvent(CraftEventFactory.java:701)
	at net.minecraft.server.v1_6_R2.EntityPlayer.closeInventory(EntityPlayer.java:710)
	at org.bukkit.craftbukkit.v1_6_R2.entity.CraftHumanEntity.closeInventory(CraftHumanEntity.java:321)
	at com.github.dsh105.echopet.listeners.MenuListener.onInventoryClick(MenuListener.java:74)
	at sun.reflect.GeneratedMethodAccessor180.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30)
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:478)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:463)
	at net.minecraft.server.v1_6_R2.PlayerConnection.a(PlayerConnection.java:1399)
	at net.minecraft.server.v1_6_R2.Packet102WindowClick.handle(SourceFile:31)
	at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:230)
	at net.minecraft.server.v1_6_R2.PlayerConnection.e(PlayerConnection.java:116)
	at net.minecraft.server.v1_6_R2.ServerConnection.b(SourceFile:37)
	at org.spigotmc.netty.NettyServerConnection.b(NettyServerConnection.java:125)
	at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:592)
	at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:239)
	at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:481)
	at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:413)
	at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
Caused by: java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
	at java.util.ArrayList$Itr.next(Unknown Source)
	at com.github.dsh105.echopet.listeners.MenuListener.onInventoryClose(MenuListener.java:183)
	at sun.reflect.GeneratedMethodAccessor159.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:425)
	... 27 more