Minecraft serveur

Bonjour,
mon server minecraft allai tres bien depuis ce matin et depui quand je l'ouvre je ne peut plus me connecter
sa me met sa dans les info du serveur

[INFO] Starting minecraft server version Beta 1.6.6
[INFO] Loading properties
[INFO] Starting Minecraft server on *:25565
[INFO] Preparing level "world"
[SEVERE] Unexpected exception
java.lang.NullPointerException
at dn.c(SourceFile:81)
at dh.a(SourceFile:1848)
at hf.d(SourceFile:471)
at hb.c(SourceFile:75)
at hb.b(SourceFile:96)
at dh.c(SourceFile:329)
at dh.a(SourceFile:286)
at dh.e(SourceFile:290)
at dh.a(SourceFile:227)
at ok.a(SourceFile:51)
at dh.c(SourceFile:202)
at dh.<init>(SourceFile:179)
at dn.<init>(SourceFile:34)
at net.minecraft.server.MinecraftServer.a(SourceFile:201)
at net.minecraft.server.MinecraftServer.c(SourceFile:162)
at net.minecraft.server.MinecraftServer.run(SourceFile:284)
at bo.run(SourceFile:422)






pouvez vous m'aider?

merci