Error Plugin Permission

[ghost]

01:48:20 [ERROR] [Pokkit] Could not pass event PlayerJoinEvent to GroupManagerX vGMBuildVer (Phoenix)+1
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at nl.rutgerkok.pokkit.plugin.BukkitEventManager.fireEvent(BukkitEventManager.java:64)
at nl.rutgerkok.pokkit.plugin.BukkitEventManager.callEvent(BukkitEventManager.java:49)
at nl.rutgerkok.pokkit.plugin.PokkitPluginManager.callEvent(PokkitPluginManager.java:79)
at nl.rutgerkok.pokkit.pluginservice.EventTranslator.callUncancellable(EventTranslator.java:41)
at nl.rutgerkok.pokkit.pluginservice.PlayerConnectEvents.onPlayerJoin(PlayerConnectEvents.java:29)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at cn.nukkit.plugin.MethodEventExecutor.execute(MethodEventExecutor.java:29)
at cn.nukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:56)
at cn.nukkit.plugin.PluginManager.callEvent(PluginManager.java:553)
at cn.nukkit.Player.doFirstSpawn(Player.java:785)
at cn.nukkit.Player.sendNextChunk(Player.java:741)
at cn.nukkit.Player.checkNetwork(Player.java:1743)
at cn.nukkit.Server.tick(Server.java:1010)
at cn.nukkit.Server.tickProcessor(Server.java:794)
at cn.nukkit.Server.start(Server.java:773)
at cn.nukkit.Server.(Server.java:464)
at cn.nukkit.Nukkit.main(Nukkit.java:68)
Caused by: java.lang.NullPointerException
at a.e.b.addAttachment(NukkitPlayer.java:501)
at cn.nukkit.Player.addAttachment(Player.java:429)
at cn.nukkit.Player.addAttachment(Player.java:424)
at nl.rutgerkok.pokkit.player.PokkitPlayer.addAttachment(PokkitPlayer.java:206)
at org.anjocaido.groupmanager.permissions.BukkitPermissions.updatePermissions(BukkitPermissions.java:163)
at org.anjocaido.groupmanager.permissions.BukkitPermissions.updatePermissions(BukkitPermissions.java:134)
at org.anjocaido.groupmanager.permissions.BukkitPermissions$PlayerEvents.onPlayerJoin(BukkitPermissions.java:451)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302)
... 21 more