permissions plugin. i need help

everytime i use plugins or the permissions itself to promote somebody, this happens.

Code:

>pr skyy0731 promote Member

[Permissions] No world specified. Defaulting to default world.
2011-08-14 09:23:13
[WARNING] Unexpected exception while parsing console command
org.bukkit.command.CommandException: Unhandled exception executing command 'pr' in plugin Permissions v3.1.6
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:37)
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:129)
at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:312)
at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:480)
at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:465)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:361)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)
Caused by: java.lang.NullPointerException
at java.util.HashSet.<init>(Unknown Source)
at com.nijiko.data.YamlGroupStorage.getTracks(YamlGroupStorage.java:284)
at com.nijiko.permissions.PermissionWorld.getTracks(PermissionWorld.java:168)
at com.nijiko.permissions.ModularControl.getTracks(ModularControl.java:532)
at com.nijikokun.bukkit.Permissions.Permissions.onCommand(Permissions.java:731)
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:35)
... 6 more

link to my permissions folders here