To my dismay when I loaded up Amarok 2.0.2 after a upgrade from 8.10 (Intrepid) to 9.04 (Jaunty) I was getting a error that my sound card was broken.
However, sound worked in all other applications. The solution is to:
sudo apt-get install phonon-backend-xine
sudo apt-get remove phonon-backend-gstreamer
after that restart Amarok (if it wasn’t already closed) and hooray sound works!.