Sony Vegas "An Exception has occured" Question?

I've seen several forums online of people who have had this problem, but no one was giving a straight answer. When I try to import video files into Sony Vegas 9, it says something about an error occurring and an exception or something or other. Then when I click details it gives me a bunch of incoherent, technical mumbo jumbo. Then when I click ok, the program closes. If anyone could help me I'd be greatly appreciative.