Dutch bought a Panasonic VHS to DVD burner, but it won't play on any other DVD players. Leo says that's because Dutch made a multi-session DVD. Or, it could be that he forgot to finalize the DVD. It also could be a different type of DVD, such as DVD-RAM, which could confuse a normal DVD player.
Since it will work on his computer, he should try ripping the DVD on his PC and reburn it. Windows Movie Maker or Adobe Premiere Elements would work. There are also cloning programs which he can use to just clone the DVD. CloneDVD by Slysoft is one Leo recommends.