MyHorse Error

10.08 07:34:22 [Server] INFO ... 15 more
10.08 07:34:22 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
10.08 07:34:22 [Server] INFO at com.dogonfire.myhorse.MyHorse.onCommand(MyHorse.java:359)
10.08 07:34:22 [Server] INFO at com.dogonfire.myhorse.Commands.onCommand(Commands.java:209)
10.08 07:34:22 [Server] INFO at com.dogonfire.myhorse.Commands.CommandList(Commands.java:826)
10.08 07:34:22 [Server] INFO at com.dogonfire.myhorse.MyHorse.getHorseNameColorForPlayer(MyHorse.java:200)
10.08 07:34:22 [Server] INFO at com.dogonfire.myhorse.PermissionsManager.getGroup(PermissionsManager.java:264)
10.08 07:34:22 [Server] INFO at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.getWorldPermissionsByPlayerName(WorldsHolder.java:512)
10.08 07:34:22 [Server] INFO at org.anjocaido.groupmanager.dataholder.worlds.WorldsHolder.getWorldDataByPlayerName(WorldsHolder.java:462)
10.08 07:34:22 [Server] INFO at org.bukkit.craftbukkit.v1_6_R2.CraftServer.matchPlayer(CraftServer.java:366)
10.08 07:34:22 [Server] INFO at org.apache.commons.lang.Validate.notNull(Validate.java:203)
10.08 07:34:22 [Server] INFO Caused by: java.lang.IllegalArgumentException: PartialName cannot be null
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:419)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:486)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:226)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:590)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.DedicatedServerConnection.b(SourceFile:30)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.ServerConnection.b(SourceFile:37)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.PlayerConnection.e(PlayerConnection.java:116)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.NetworkManager.b(NetworkManager.java:296)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.Packet3Chat.handle(SourceFile:49)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.PlayerConnection.a(PlayerConnection.java:837)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.PlayerConnection.chat(PlayerConnection.java:880)
10.08 07:34:22 [Server] INFO at net.minecraft.server.v1_6_R2.PlayerConnection.handleCommand(PlayerConnection.java:962)
10.08 07:34:22 [Server] INFO at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchCommand(CraftServer.java:523)
10.08 07:34:22 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:191)
10.08 07:34:22 [Server] INFO at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
10.08 07:34:22 [Server] INFO org.bukkit.command.CommandException: Unhandled exception executing command 'myhorse' in plugin MyHorse v0.1.3
10.08 07:34:22 [Server] SEVERE null
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player Alphajuggernut's group '' in config.yml!
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player lautus's group '' in config.yml!
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player lautus's group '' in config.yml!
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player RickRollTheTroll's group '' in config.yml!
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player DarkishDuck98's group '' in config.yml!
10.08 07:34:22 [Server] INFO [MyHorse v0.1.3] Could not get horse name color from player skyman5667's group '' in config.yml!
10.08 07:34:21 [Server] INFO [MyHorse v0.1.3] No language strings found for YouCannotClaimThisHorse!