Some of the newer discs that are being released are designed for newer DVD players that can handle the upgraded discs (yes there is a difference between the disc format they used a few years ago and now for some discs - cannot recall the names offhand but it's sometimes described and explained on some of those Brentwood releases in their DVD Dictionary sections). In some cases, an older player will have troubles playing said discs. As I understand it, this is the case with the Universal releases which may very well play fine on another DVD Player.
What you might be talking about there is "Dual Layer" discs JaseSF. A newer format of dvd as JaseSF mentioned, Dual Layer Dvds can have trouble playing on some older style dvd players. Most of the time a firmware upgrade will solve the problem, but at work we occasionally need to send a player away to replace the drive completely.
A dvd player not suited to handling these dvds will just refuse to read them, not skip them [as far as I know].
The only trouble I've ever had with my dvds are ones which are scratched in just the wrong place, or copied dvds on a poor quality transfer.
Hmmm... its funny but most dvds players released here are quite easy to or come standard as multi-zoned, and most do both PAL and NTSC...