Bukkit

I get this error, if 2 players joined a Quake Arena:

[11:04:40] [Server thread/WARN]: java.lang.NullPointerException
[11:04:40] [Server thread/WARN]:     at com.Geekpower14.Quake.Arena.SArena.updateScore(SArena.java:375)
[11:04:40] [Server thread/WARN]:     at com.Geekpower14.Quake.Arena.SArena.joinArena(SArena.java:276)
[11:04:40] [Server thread/WARN]:     at com.Geekpower14.Quake.Commands.JoinCommand.onCommand(JoinCommand.java:48)
[11:04:40] [Server thread/WARN]:     at com.Geekpower14.Quake.Commands.MyCommandExecutor.onCommand(MyCommandExecutor.java:128)
[11:04:40] [Server thread/WARN]:     at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
[11:04:40] [Server thread/WARN]:     at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:192)
[11:04:40] [Server thread/WARN]:     at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServer.java:546)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.PlayerConnection.handleCommand(PlayerConnection.java:937)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.PlayerConnection.a(PlayerConnection.java:812)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.PacketPlayInChat.a(PacketPlayInChat.java:28)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.PacketPlayInChat.handle(PacketPlayInChat.java:65)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.NetworkManager.a(NetworkManager.java:147)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.ServerConnection.c(SourceFile:134)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:657)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:259)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:540)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:446)
[11:04:40] [Server thread/WARN]:     at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617)

I recreated the Quake folder, disable other Plugins, updated WorldEdit and downloaded Quake again.
I testet Spigot (#1225) and CraftBukkit (#2974).
Please fix that error!