I have been running into this same issue since we upgraded from G5’s to Intel MacPros. Constant “new tape has been inserted” messages in FCP; flashing video input while shuttling, errors finding timecode. Seems to me like there is a big problem with the deck control portion of the card.
Running an 8 core MacPro with 10.5.2 OS, FCP 6.0.2, Quicktime 7.4.1, BlackMagic Decklink HD Pro Dual Link. Using it with a Sony HDCam SRW-5500 deck.
Has anyone made any headway with this issue…?