Some VOBs look weird in Vegas. I deal with this before. Another solution for editing (have to render):
1.- Have VOB in your hard drive (rip DVD with any tool you want).
2.- Use DVD2AVI to make a d2v file. Demux audio to put on Vegas timeline.
3.- Use VFAPI to make the d2v an AVI compliant. VERY FAST and easy.
4.- Drop the AVI on Vegas (with the corresponding audio) timeline and edit as a normal AVI.
5.- Render. DONE.
Always work. Same process as capturing from DVD player without the capturing time (just ripping DVD time).
All the best.
EOR