Comment 5 for bug 742335

As a workaround, one can force gstreamer to use a different plugin for playing mp3s:

http://ubuntuforums.org/showthread.php?p=10876312

sudo apt-get remove gstreamer0.10-plugins-bad gstreamer0.10-plugins-ugly

sudo apt-get install gstreamer0.10-plugins-bad-multiverse gstreamer0.10-plugins-ugly-multiverse gstreamer0.10-fluendo-plugins-mp3-partner