pvp arena error

[SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'pa' in plugin pvparena vv0.4.4.10
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:42)
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:165)
	at org.bukkit.craftbukkit.CraftServer.dispatchCommand(CraftServer.java:378)
	at net.minecraft.server.NetServerHandler.handleCommand(NetServerHandler.java:757)
	at net.minecraft.server.NetServerHandler.chat(NetServerHandler.java:722)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:715)
	at net.minecraft.server.Packet3Chat.a(Packet3Chat.java:33)
	at net.minecraft.server.NetworkManager.b(NetworkManager.java:226)
	at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:93)
	at net.minecraft.server.NetworkListenThread.a(SourceFile:108)
	at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:527)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
Caused by: java.lang.NullPointerException
	at net.slipcor.pvparena.managers.PlayerManager.getTeam(PlayerManager.java:250)
	at net.slipcor.pvparena.managers.CommandManager.parseWatch(CommandManager.java:201)
	at net.slipcor.pvparena.arenas.Arena.parseCommand(Arena.java:276)
	at net.slipcor.pvparena.PVPArena.onCommand(PVPArena.java:278)
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:40)
	... 12 more