I've had this problem before when I had to burn a tv series dvd for a friend of mine. Basically taking xvid files from the net and burning them on a DVD+R DL. I used ConvertXtoDVD to do this, it made a nice menu and authored the disc. The disc wouldn't play in any of my old dvd players but played fine in my oppo and the ps3.
I'm guessing since you bought series dvds the application was pretty much the same. If the dvds weren't pressed, and if they were DL dvd's, its possible the laser on your dvd players just couldn't read the layers properly.