Hey, Today I was on my server and noticed that my prefix and suffix was reversed, I went and fixed it all but when I started back up my server, The group manager gave me A error in the CMD Panel, I looked through all the configs but nothings out of place or wierd,

Error:
[/spoiler]2013-09-23 10-54
=============================== GM ERROR LOG ===============================
= ERROR REPORT START - 2.0 (2.11.1) (Phoenix) =

java.lang.NullPointerException
at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:171)
at org.anjocaido.groupmanager.GroupManager.onCommand(GroupManager.java:1872)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:192)
at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchCommand(CraftServer.java:523)
at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchServerCommand(CraftServer.java:512)
at net.minecraft.server.v1_6_R2.DedicatedServer.ar(DedicatedServer.java:262)
at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:227)
at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:486)
at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:419)
at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)

============================================================================[/spoiler]

Configs:
[spoiler]# Group inheritance