903 patch server error?
This is a connection issue between you and the patch server. One of the most frequent causes of this is not having the right psobb.exe and online.exe in your folder. Make sure you extracted properly.

It may also be the case that the patch server's having some issues. If you're sure you replaced your exes properly, try again. If you still have issues, request help in the shoutbox or in the help forums linked above. The patch server may simply need a restart.