Doctor M said:

@OmegaMattman - Always try a different DVD drive if that happens. Lasers get weaker with age and sometimes worse at reading discs.

Yeah, I was hoping that was the problem. Dug out my laptop...and every old DVD drive I still have around the house. No success.

Might pick up a cheap drive before the weekend is out and give it a shot.

Off topic, the DVD in question was a widescreen reconstruction of the Star Trek: The Motion Picture "Special Longer Version" I completed in 2010. I don't remember why, but I did not generally upload it...and only gave it to a handful of people who do not seem to be able/willing to help me get a duplicate :/