problems with jvc dvd player.

My brother has a high dollar refurbished jvc dvd player with three stage progressive scan. It will play new or rented dvd's just fine, but won't play any of my backups (I'd rather let him borrow my backups than my orinal copy's for obvious reasons). My backups play just fine on my rca dvd vcr combo, my friends hitachi dvd vcr combo, and my moms cheap sanyo dvd player. Any suggestions or insight on what might be the problem. All my backups are on ritek ridata g04 media. Thanks.