[06:13:59 ERROR]: Could not pass event FactionChatPlayerChatEvent to FactionChat v1.10.0-PRE-4
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot.jar:git-Spigot-7745d45-02d704b]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-7745d45-02d704b]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-7745d45-02d704b]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-7745d45-02d704b]
        at nz.co.lolnet.james137137.FactionChat.FactionChatListener.onChat(FactionChatListener.java:140) [FactionChat.jar:?]
        at nz.co.lolnet.james137137.FactionChat.FactionChatListener.onPlayerChat(FactionChatListener.java:121) [FactionChat.jar:?]
        at nz.co.lolnet.james137137.FactionChat.FactionChatListener$1.execute(FactionChatListener.java:58) [FactionChat.jar:?]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) [spigot.jar:git-Spigot-7745d45-02d704b]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-7745d45-02d704b]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:484) [spigot.jar:git-Spigot-7745d45-02d704b]
        at net.minecraft.server.v1_10_R1.PlayerConnection.chat(PlayerConnection.java:1273) [spigot.jar:git-Spigot-7745d45-02d704b]
        at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.java:1211) [spigot.jar:git-Spigot-7745d45-02d704b]
        at net.minecraft.server.v1_10_R1.PacketPlayInChat$1.run(PacketPlayInChat.java:39) [spigot.jar:git-Spigot-7745d45-02d704b]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [?:1.7.0_80]
        at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_80]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [?:1.7.0_80]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [?:1.7.0_80]
        at java.lang.Thread.run(Thread.java:745) [?:1.7.0_80]
Caused by: java.lang.NoClassDefFoundError: com/gmail/nossr50/util/player/UserManager
        at nz.co.lolnet.james137137.FactionChat.API.McMMOAPI.onPlayerFactionChat(McMMOAPI.java:30) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_80]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_80]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_80]
        at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_80]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-7745d45-02d704b]
        ... 17 more