When I try to play any MP3 encoded song in Rhythmbox, the seek bar is disabled. Upon trying to play the same files in Totem, the same problem appears again.
I think that the problem started after following option C in this guide, and then undoing it.
I've tried reinstalling
gstreamer0.1-fluendo-mp3, which are the packages I think Rhythmbox is asking for upon playing a MP3 encoded file.
Running Ubuntu 10.04, recently updated.