I've heard that Sonic's DVD authoring app is pretty good, but complex. Is it the complexity of the app that's been creating problems?
I've been using a Mac, so I can't really recommend something for the PC from experience, but I'd suggest looking into Adobe's Encore, or Sony's DVD Architect, but I don't know if DVD Architect has to be used from within Vegas?
I'd like to know what works out best, I plan to do some DVD authoring on PC pretty soon.