There are 3 different problems. It sounds like, if it’s not playing correctly, it’s not being correctly formatted to be a standard DVD. Maybe the frame rate isn’t the correct value and such. Your program isn’t doing what it’s supposed to do. Take a look at DVDDemystified.com
It’s impossible to burn DVD’s on a PC that every player can play. Some older ones could only read -R’s, some only +R’s and some couldn’t play any recorded ones at all. A lot of them can’t play discs that aren’t Finalized correctly by the PC burner and lots of burners don’t finalize correctly. You can download DVDInfoPro and check his discs, if they look OK then he should go to videohelp.com and check the capability of his players. If his discs are correct he may have to upgrade to newer players.