Ah, perhaps you were using Nero Recode to shrink the dvds down to size?
In any case, test the dvds you are making before you burn to a disk. The output from Shrink should be on the hard drive. VLC media player can play them in either file form or ISO form, depending on which one you have decided to make in Shrink. www.videolan.org
Make certain they play before burning.
Next, test the burned dvds in the computer. Again, VLC is good for this.
If they play here in the computer, that means your stand alone dvd player is a bit picky about your current disks. Have you changed the type of disks you are using?
Tell us the type of disks, and what speed you are burning them. Sometimes slowing down the burn speed will give you a slightly better result...up to a point. Try 16x speed media at 8x.
The other possible problem that has just occurred to me is that you may not be removing all the protection from your dvds. DVDDecrypter hasn't been updated in many years now, and is not effective on many newer disks. Try DVDFab HD Decrypter to decrypt and rip the dvds to the hard drive. It is the free section of DVDFab and will continue to work even after the trial for the main section expires. http://www.dvdfab.com/free.htm I'm not so sure this is the problem though, since Shrink normally won't work well at all on dvds that still have bad structure.