Question about playing DVDR's of MP3's (RE: BDP-S185 )

[Groo The Perverted]

A friend of mine has a Sony BDP-S185 Bluray player, and I put a bunch of MP3's on a DVD-R for him, and he said it will not play. I also put them on a thumbdrive and he connected it via the USB drive, and it also would not play.

At first I thought maybe he had to switch over to another mode, like I did on an old phillips Divx player, switching between DVD and the USB drive, but he's had no problems playing media on the thumbdrive or the DVDR's before, but now it's not recognizing the MP3's.

Is there any reason this should be doing this? Would appreciate the help. Thanks.