I faced the same problem with you.It has to do with with Motherboard and not with OS (Win7 or Vista). DeckLink conflicts IRQ with some other card.
You could try changing position of DeckLink to some other PCI slot.
I used MB ASUS P5E64 WS Evolution X48 chipset and it was ok.When I used MB Gigabyte GA-EX58-UD5 X58 chipset PCI SLOT and I made all possible changes, none of them worked.
Finally, I used ASUS P6T6 WS Revolution X58 chipset 6 PCI SLOT which made it work perfectly.
Configuration:
ASUS P6T6 WS Revolution
3ware 9650SE-8LPML……PCI slot 01
GeForce GTX 470……….PCI slot 03
DeckLink HD Extreme…..PCI slot 06
i hope to helped you.
DeckLink HD Extreme
Intensity Pro
Broadcast Converter