I've backed up several of my dvd's using dvd shrink and burning them with Nero 6. My problem is that the first dozen or so worked perfectly and the last few play in my cpu's drive only and not on any of my other dvd players. I have a Kenwood dvd player, X-box, and PS2. My burner is a Pioneer DVR-104. I'm still a novice, so any help would be greatly appreciated.