I hate to sound like Mr. Obvious here, but did you choose Audio CD under Disk Selection? I'm listening to a music CD as I write this on my Power Mac G4. It's pretty ragged, but it works.
Oops... the CD doesn't want to eject until after I reboot. Oh, well.
Folks: Just posted on another thread on the issues with "kernel panic" in iMac G4, where I mentioned that in my Wheezy iMac install I also don't have CD/DVD drive capability either. The CD just "lies there" if you know what I mean--had to use command line to eject, etc. Not a major problem as I still have the OSX side going to do that . . . but it seems like fairly basic function that Debian should "take care of" in its pursuit of Linux "top dog" position??? Guess not.