Minecraft probleme de creation de serveur

Bonjour, j'ai el probleme suivant en essayant de créer mon propre serveur survivor dans minecraft, j'ai fais mon update java et tout pis quand j'execute server_gui ben sa me donne sa pis je trouve pas de solution.

[INFO] Starting minecraft server version 0.2.1
[INFO] Loading properties
[INFO] Starting Minecraft server on *:25565
[INFO] Preparing level "world "
[INFO] Preparing start region
[SEVERE] Unexpected exception
java.lang.RuntimeException: Failed to check session lock, aborting
at dy.<init>(SourceFile:168)
at dy.<init>(SourceFile:144)
at ee.<init>(SourceFile:35)
at net.minecraft.server.MinecraftServer.c(SourceFile:139)
at net.minecraft.server.MinecraftServer.d(SourceFile:130)
at net.minecraft.server.MinecraftServer.run(SourceFile:186)
at bm.run(SourceFile:480)