Here's how I worked around it on my machine:
I uninstalled amarok, and all xine-related packages I had ( might not be necessary though ) and I deleted the ~/.xine folder.
Then I reinstalled amarok & it's xine dependencies, and when I tried to play an mp3, I got the kdialog asking me to install libxine-extracodecs, which I did. After restarting amarok, mp3's played fine again.
I can confirm this bug.
Here's how I worked around it on my machine:
I uninstalled amarok, and all xine-related packages I had ( might not be necessary though ) and I deleted the ~/.xine folder.
Then I reinstalled amarok & it's xine dependencies, and when I tried to play an mp3, I got the kdialog asking me to install libxine- extracodecs, which I did. After restarting amarok, mp3's played fine again.
I hope this helps something.