Just for the sake of context, re videobruce's issues playing back some Mag H2160-created DVDs on his Oppo and PCs:, it should be noted/remembered this issue is more common than people realize, across many brands of DVD recorder- not just the Magnavox or Funai-based units.
Up until recently, and even now and then with current models, there were a startling number of reports that the super-popular Panasonics created goofball DVDs that didn't play nice outside the recorder, primarily showing problems with sound losing sync. The old, advanced Toshiba XS series, which has a cult following here to rival Jim Jones, is notorious for authoring DVDs that appear as defective or blank when played outside the recorder. Another cult favorite, the original JVC models with the LSI encoder, also authors somewhat off-spec discs that can be taken as defective or blank: dedicated players don't register a DVD is loaded, and PC software used to make backups will either report the JVC VOB structure as "defective" and try to repair it, or fail 90% thru a backup attempt. I have owned practically every Pioneer DVD/HDD machine since the first, and while they've generally burned widely-compatible DVDs, occasionally I find they skip or more likely freeze-reset when played in Phillips or Toshiba DVD players (which normally will play absolutely anything you put in them.) Ditto the older, highly prized Sony recorders. Some models make somewhat more compatible DVDs using "real time", others are better with HS lossless dubs: its all random.
Burned DVDs are a technological kludge, a remarkably effective kludge usually, but subject to inconsistencies. The two consistent factors I've seen over the years are that 8x media yields better compatibility than 16x in most recorders (and some PCs depending on the burner+software installed), and "problem" burned discs will almost always play just fine in the junkiest, cheapest $29 drug store brand DVD players like Coby. Its worth keeping a "crap" player around for such emergencies. The really weird thing is, while these cheapo players have no trouble with iffy burned discs, they often balk at commercially pressed discs, particularly TV show season sets. Go figure.