When i start up a server, it stops loading anymore of the gui, than shown in the attached picture. Minecraft clients are unable to join the server, as well as making joinable singleplayer-lan-servers.
I have tested this on two different computers. And on versions downloadable from mojang.com, back to 13w36b, in which i found that the downloaded file did not work, but an, on my computer, already existing server file of this version worked flawlessly.

When trying to run the server .jar or .exe in an emty folder, it seemed that it would not create a world nor a server.propeties file

edit: I have now tried running the server in the console without gui, and posted the console output i files.
I ran the server in three different cases, with different resulting console output.

when running the server with an existing map, it runs fine, but players trying to connect get the error message:
Internal Exception: io.netty,handler.timeout.ReadTimeoutException
or sometimes the error message:
Internal Exception: io.netty.handler.codec.DecoderException: java.io.IOException: The recieved string length is longer than the maximum allowed (50>16)