The exact wording of the error:
PGC “clip2 name” has an error at 00:00:00:11.
Unknown error.
(DVD error – 1)
The first time it came up with a different clip and after viewing this in the monitor, it seemed fine. The next time it came up with this clip and I’ve tried reimporting it, reexporting it, recompressing it and almost every other option I can think of – it still is stuck on that error.