I have solved the problem, which turned out to be a couple of frames with some sort of problem which caused the render to abort. Removing those frames allowed the whole thing to build successfully, and I lost a fraction of a second of footage from the corrupted source footage. It's for personal use; I can live with that tiny flaw, peeving as it is. (I had previously succeeded in rendering the whole video, so I am a little puzzled by the problem.)
Isolating those faulty frames was time-consuming. I tried a render of the whole timeline by pressing enter. This got quite a long way through and aborted, leaving me with a green and a red bit on the timeline. I established the that everything after a later point worked fine. Doing the failed bit in ever-smaller chunks, kind of a binary search, eventually isolated the couple of frames involved. If I had a way to regenerate the footage I would have been happier, but eliminating those few frames is a passable solution.
Glad that you found the cause of the issue, and a workaround to producing the DVD.
Now, regarding those bad Frames:
Did you have any gaps in the Video portion of the Timeline? Those can kill a Transcode?
What was the format/CODEC of the bad footage? Some GOP structures can also cause Transcode issues. This especially happens, when one has done a Cut, that removed a preceding I-frame, and the Cut is now on only the "difference Frames." Without the necessary I-frame to draw from, the program has real issues. This ARTICLE will give some more background.
Format: MPEG. Cuts in the segment: None - until I excised a couple of frames to get around the problem.
The entire thing had previously rendered without problems, so the apparent corruption in part of the video file during the time I was editing is a little bothersome, so I'll do a disk scan for my peace of mind, which can only be done during a boot and will take time (2GB drives have a down side!).
Thank you for your help!