I'm trying to capture a VHS tape (made in 1993.) The picture looks fine on the TV screen but when viewed through my tv card there is a horizontal rainbow of colors in the top 1/8 of the picture. What I'm talking about can be seen here:

http://xch074.chemistry.montana.edu/~banderso/images/lines.jpg

It's strange because this has happened to me before when I tried to convert a VHS tape that I made on an old 2head vcr (I figured the lines were just because of a crappy initial recording.) This tape, on the other hand, is a commercial grade tape. Is this macrovision of some sort?

Specs:
STB tv pci (using composite in)
Virtualdub 1.4d (using Mjpeg codec)