Group Manager Error Bukkit 1.3.1.R2

21:03:18 [INFO] [GroupManager] Enabling GroupManager v2.0 (2.9.3) (Phoenix)
21:03:18 [SEVERE] GroupManager - SEVERE - ===================================================
21:03:18 [SEVERE] GroupManager - SEVERE - = ERROR REPORT START =
21:03:18 [SEVERE] GroupManager - SEVERE - ===================================================
21:03:18 [SEVERE] GroupManager - SEVERE - === PLEASE COPY AND PASTE THE ERROR.LOG FROM THE ==
21:03:18 [SEVERE] GroupManager - SEVERE - = GROUPMANAGER FOLDER TO AN ESSENTIALS  DEVELOPER =
21:03:18 [SEVERE] GroupManager - SEVERE - ===================================================
21:03:18 [SEVERE] GroupManager - SEVERE - null
21:03:18 [SEVERE] GroupManager - SEVERE - ===================================================
21:03:18 [SEVERE] GroupManager - SEVERE - = ERROR REPORT ENDED =
21:03:18 [SEVERE] GroupManager - SEVERE - ===================================================
21:03:18 [SEVERE] Error occurred while enabling GroupManager v2.0 (2.9.3) (Phoenix) (Is it up to date?)
java.lang.IllegalArgumentException
        at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:230)
        at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:85)
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:365)
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
        at org.bukkit.craftbukkit.CraftServer.loadPlugin(CraftServer.java:265)
        at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:247)
        at net.minecraft.server.MinecraftServer.i(MinecraftServer.java:296)
        at net.minecraft.server.MinecraftServer.d(MinecraftServer.java:275)
        at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:225)
        at net.minecraft.server.DedicatedServer.init(DedicatedServer.java:140)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:378)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
Caused by: java.lang.NullPointerException
        at org.anjocaido.groupmanager.GMConfiguration.load(GMConfiguration.java:75)
        at org.anjocaido.groupmanager.GMConfiguration.<init>(GMConfiguration.java:38)
        at org.anjocaido.groupmanager.GroupManager.prepareConfig(GroupManager.java:314)
        at org.anjocaido.groupmanager.GroupManager.onEnable(GroupManager.java:153)
        ... 12 more