Were you ever able to resolve this? I tried my PV-GS320 via USB and get the same black screen but broadcasting deal as you. I've tried this in XP Home SP2 with YIM v 7 and Vista Ultimate SP2 with YIM 9. Both give the same black screen but are recognized as web cams by the systems. In both cases I can switch the GS320 to DV mode and import video over USB and firewire ports.
I have a Logitech QuckCam STX Communicate that works fine in both XP and Vista but it's my nature to play around with my toys
