14:35:00 [SEVERE] Could not pass event PlayerChatEvent to MonsterIRC
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:303)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:459)
at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:787)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:765)
at net.minecraft.server.Packet3Chat.handle(Packet3Chat.java:34)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:114)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.IncompatibleClassChangeError: Expecting non-static method com.gmail.nossr50.mcMMO.getPlayerProfile(Lorg/bukkit/entity/Player;)Lcom/gmail/nossr50/datatypes/PlayerProfile;
at org.monstercraft.irc.plugin.managers.listeners.MonsterIRCListener.onChat(MonsterIRCListener.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
... 11 more

I have seen this for a few versions of MonsterIRC now. Been holding back from updating.