No audio gaps in Premiere timeline.
Main video and audio are one, single 65 minute video clip. Only editing done to that was trimming the ends and adding constant power audio fade in and out, and a dip to black at the end.
There is a second audio track with 6 seconds of overlay applause at the beginning. This was extracted from another video, but it was saved out as a standalone wav clip.
All the extra graphics are up front, at the intro. I tested making a EN project out of just the first 5 minutes, and that will compile into a DVD iso image without error.
Baffled at this point as to the cause...