When adding new items to Amarok in Ubuntu 9.04 the items do not want to play and Amarok only loops through the whole playlist and no sound is heard.
Follow the steps below in order to solve the problem
Remove GStreamer ffmepeg video plugin, GStreamer extra plugins and Movie Player (GStreamer) via Add/Remove (Applications -> Add/Remove)
Open a new Terminal session and type in the following command to install phonon-backend-xine: sudo apt-get install phonon-backend-xine
Enter you’re password and hit enter. Now phonon-backend-xine should be installed.
Open Amarok and the mp3 files should play.