Taolar, the problems you describe sound similar to what happened when I tried to open up video captured in virtual dub using HuffyUV. It displayed and captured fine in vdub, the video files played fine when opened in windows media player but when I opened them in Vegas version 4, it came out all garbled (all frames throughout). I posted an example on page 2 of the thread I started about using HuffyUV.
http://www.originaltrilogy.com/forum/messageview.cfm?catid=12&threadid=7640&STARTPAGE=2
I don't want to hijack the thread but may I ask if this is similar to what you have experienced?

As for the original poster, I sounds like Zion and Taolar both have good solutions.