You need at least 64-bit 66Mhz PCI busses. Your motherboard has only 32-bit PCI busses. Don’t be fooled by the size of the DeckLink card.
It’s not the bits that count, but the speed of the PCI-bus (66 mhz instead of the 33mhz of a regular 32-bit PCI). BMD should have made the boards 1 inch bigger, so an empty part would fit in the 64-bit part of the bus, it would make support much easier.
For a timeline to play, you need several channels of video. That’s why you can get away with it using Deck Control but not with PPro.
-Yves