So I have 4 servers linked up with Bungeecord, and all using MonsterIRC to chat cross servers..Well on of the servers has an issue with outgoing messages. They can see other messages just fine, but cant send them. Any help?

24.03 13:32:17 [Server] INFO ... 14 more
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
24.03 13:32:17 [Server] INFO at java.lang.reflect.Method.invoke(Method.java:601)
24.03 13:32:17 [Server] INFO at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
24.03 13:32:17 [Server] INFO at sun.reflect.GeneratedMethodAccessor586.invoke(Unknown Source)
24.03 13:32:17 [Server] INFO at org.monstercraft.irc.plugin.managers.listeners.MonsterIRCListener.onChat(MonsterIRCListener.java:62)
24.03 13:32:17 [Server] INFO Caused by: java.lang.NoClassDefFoundError: com/gmail/nossr50/util/Users
24.03 13:32:17 [Server] INFO at java.lang.Thread.run(Thread.java:722)
24.03 13:32:17 [Server] INFO at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
24.03 13:32:17 [Server] INFO at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
24.03 13:32:17 [Server] INFO at java.util.concurrent.FutureTask.run(FutureTask.java:166)
24.03 13:32:17 [Server] INFO at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
24.03 13:32:17 [Server] INFO at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
24.03 13:32:17 [Server] INFO at org.spigotmc.netty.NettyNetworkManager$2.run(NettyNetworkManager.java:105)
24.03 13:32:17 [Server] INFO at net.minecraft.server.v1_5_R2.Packet3Chat.handle(Packet3Chat.java:44)
24.03 13:32:17 [Server] INFO at net.minecraft.server.v1_5_R2.PlayerConnection.a(PlayerConnection.java:840)
24.03 13:32:17 [Server] INFO at net.minecraft.server.v1_5_R2.PlayerConnection.chat(PlayerConnection.java:901)
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:461)
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:26)
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
24.03 13:32:17 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
24.03 13:32:17 [Server] INFO org.bukkit.event.EventException
24.03 13:32:17 [Server] SEVERE Could not pass event AsyncPlayerChatEvent to MonsterIRC v1.73

Your problem is with the dependencies for MCMMO. There was a method name change in recent build of MCMMO that broke MonsterIRC. I have a working build on my GitHub page if you need the source. https://github.com/MutinyCraft/MonsterIRC