Its probably something you have on the timeline that is causing
Vegas to be behaving like that ( a corrupt video clip or codec issue or
something like that). Try a basic render with some basic standard files
etc and see if the render still produces this error.
If the problem persists, do a clean Vegas re-install (you wont lose
any of your current Vegas settings).
Steve Rhoden (Cow Leader)
Film Maker & VFX Artist.
Owner of Filmex Creative Media.
Samples of my Work and Company can be seen here:
https://www.facebook.com/FilmexCreativeMedia