I have the same camera, the Sony HC42 and I was working on capturing vid for the first time last night and ran into the same issue. Mine also said DVin. And it didn't seem to matter which editing software I used, it wouldn't recognize it.
For kicks, I brought the camera into work to see if it would work on the laptop. I had to buy 4pin to 4pin for this, but i hooked it up, it recognized the camera right away, and I was able to capture from Windows Movie Maker (don't laugh, it's all i have on my notebook).
Now I am curious why it isnt working at the house. with a 4pin to 6pin on a PCI Firewire card.
I will keep tinkering, and If I find something out, I will pass it along.