It really is difficult to guess from a distance. I suspect it's either copyright control or a codec issue. The other mp3 player I use to play those "xtra" types of mp3's is Audion. See if you can get a hold of audion 3 (for osx, or 2.6 for classic). And I did a sear' & I foun many o' them under apps! I think there's at least one other mac mp3 player that can do the job but I've never tried it. To reiterate, iTunes does NOT have the ability to play 'all' mp3 types! Hope that's helpful advice.