Okay, results!
> If you have a corrupted prerender somewhere in your project, you may be able to flush it out by: TOOLS > CLEAN UP PRERENDERED VIDEO.
Alas, this did not do the trick.
> If you’re using Vegas Pro, try dropping your Dynamic RAM Preview (Options – Prefs – Video) to 128 MB. and your render threads to 1 and see if that helps.
This worked! Unfortunately it made the render take about two or three times at long but Christ, at least it WORKED.
Thanks for the help and advice everyone! I continue to love this forum.
Oliver Brackenbury
http://www.handfulofminutes.com