Can't play MP3s?

[Michael Satterwhite]

Since installing feisty, I can no longer play MP3s. I've installed the Ubuntu 
restricted package - which I thought brought in the extra codecs.

If I try to play an MP3, amarok says that it can't play MP3s. There is a 
button to install MP3 support - but it can't be used. The window asking if 
MP3 support should be installed locks solid, and neither of the buttons are 
active. The window itself cannot be closed - and the only way to get it off 
the screen is to go to a console window and kill amarok. 

What do I need to do to be able to play MP3s in Feisty?

TIA
---Michael