Look up both your player and the media at
http://www.dvdrhelp.com. They have a very good listing of both what the player should be able to play and also has rating of DVD media.
Also, some DVD authoring software have a 'Quick Eject' option in the burn process. If this option is selected, supposedely it can make the disc less likely to play on certain players. I don't why this is. ULead Movie Factory keeps warning me about it.