Does anyone know what the most common cause of DVD picture freezing up is?

I’ve been enjoying my budget priced Sony DVD player (DVP -NC665P) for almost a year until a week ago when I rented Gods And Generals. I was about two thirds way through side one of disc and the picture froze up. After about 10 seconds, it skipped to next chapter. The side two of disc, about half way through, it happened again. I’m hoping it was the disc.

My DVD player does have that pause syndrome on some discs but for only about for a half second which I can live with. Will higher grade or different brand of DVD players do better against this problem?

Thanks for your forthcoming inputs.