Hey, just an FYI since I could not find the solution to this problem on any Minecraft forum anywhere. My server started freaking out earlier this week after updating minecraft_server.jar to beta version 1.4. It would just repetaedly spit out these two errors indefinitely:
at jg.a(SourceFile:29)
at jg.b(SourceFile:37)
It’s most likely a permissions error. Check permissions on minecraft_server.jar (and server.properties? Don’t remember exactly what I did last night) and make sure that the user running the minecraft server process has access and execute rights to that file. And remember: NEVER run Minecraft as root! If you are running a Windows server, make sure that the Minecraft directory is not read only and try running the process as administrator.