There seems to be an issue with Firefox 22.214.171.124 and iTunes 7.6 on OS X with regards to M3U files. I've noticed this issue with eMusic as well. To solve this, I've included the URL of the actual streams, and if you enter that URL in Advanced --> Open Stream, that should work. There's also this script, but I haven't had a chance to try it yet.
Tell me you just didn't say that. Everytime I hear that song (The Way) I reach for a rusty nail to jab in my eyes. They are horrible. But not as bad as "Marcy's Playground". Now that will make me jump of a bridge!