I've heard that the RP-91 is compatible with DVD-R/RW & DVD+R/RW, however...I recently got the Sony DRU-500A DVD Burner, and to test this theory out, I burned some MP3's onto a DVD-RW, but it wouldn't play. I got a message that said something to the effect of "Can not play this type of disc". I also tried a DVD+RW and got the same results. I burned using Nero. I used a Memorex DVD-RW, and a Sony DVD+RW. Could the problem be that I'm trying to play an MP3, and not video? I figured since the player obviously plays MP3, it wouldn't matter. I haven't tried out DVD-R yet, as I'm afraid to end up with a $3.00 coaster.