1) Defrag the HD space you intend to capture to.
2) Launch the Video In proggy that came with ATI Multimedia Center
3) Capture the video
You can try and capture with Premiere using the Radeon by changing the capture parameters in premiere I suppose. I haven't tried it previously. It just gave me an "application already in use" error when I just tried it now.
I only use Premiere to capture DV via firewire.
I'll keep playing with it to see if I can get it to work.