What model of camcorder are you trying to capture your video from? And have you ensured that you've connected it to your computer with a FireWire (not USB) cable?
Says Premiere Pro, but the ideas are the same
-and Windows http://forums.adobe.com/message/4708997
I have NOT used it, but many say to try this for HDV capture http://strony.aster.pl/paviko/hdvsplit.htm