CDR Burning compatibility with DVD players

I use Disk Juggler and have a PlexWritter CDR burner. I burn CDs with no problem. They play on car, home, cheap and expensive CD players of all kinds. My problem is they don't play on my or my mothers DVD player. I had just assumed I couldn't. Well my mother's boyfriend using cheaper stuff is able to make CDs that play on her (Sony) DVD player. What gives? Yes I will ask him what he uses but any ideas would be helpfull. Could it possibly be the media? I use Memorex CDRs.