Very nice beauforty.
I'm expecting my 330i SE in September. Same spec, but with Aluminium trim instead of Matt titanium.
As RedStripe asks, are you sure you were playing a 'proper' MP3 disc and not an audio CD made using MP3s beauforty?
Have you tried playing MP3 discs in the CD changer yet?
If you did use MP3 discs & they did work, then I'm going to start development of my 'Running in my e90' MP3 disc right now!
Cheers.