I have a couple of those, too. Haven't had any luck with them in Linux. Broke down and got an mp3 player that plays .ogg files. But I kept the mini disk players because I have too much music on mini disks to get rid of them, and the sound is great. I love 'em and I'll keep using them until they stop working. But I have an XP computer in the back room, so I can still work with Sony's software if I need to. (Aside from my son's games, this is the only thing my Windows PC ever gets used for anymore!)
Sony generally makes quality stuff, but this kind of thing has kinda turned me away from Sony products.