I have a PC that burns dvd+r and they work fine once burnt on all of my dvd players. I recently purchased a set top dvd recorder that also uses the +r format. DVD's burned on the set top (even though they are the same format) will not play on any player except the burner itself. I can get model numbers if I need to, I am at work right now though. Any thoughts on why this may be or how I can fix it? Thanks in advance.