Hi, today I've received this error and the server crashed: Code: 2012-02-15 19:46:48 [SEVERE] java.lang.NullPointerException 2012-02-15 19:46:48 [SEVERE] at net.minecraft.server.PlayerManager.flush(PlayerManager.java:34) 2012-02-15 19:46:48 [SEVERE] at net.minecraft.server.ServerConfigurationManager.tick(ServerConfigurationManager.java:388) 2012-02-15 19:46:48 [SEVERE] at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:538) 2012-02-15 19:46:48 [SEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:435) 2012-02-15 19:46:48 [SEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:465) 2012-02-15 19:46:48 [SEVERE] Unexpected exception java.lang.NullPointerException at net.minecraft.server.PlayerManager.flush(PlayerManager.java:34) at net.minecraft.server.ServerConfigurationManager.tick(ServerConfigurationManager.java:388) at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:538) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:435) at net.minecraft.server.ThreadServerApplication.run(SourceFile:465) How can I solve?