iMovie not recognising Data Video DAC AV/DV converter

I use my DataVideo Dac-1 to capture old VHS family movies. Drop them into iMovie edit and make short DVD's. The system worked a treat with our old G4 and Panther. Have just bought a dual G5 2 Gig machine & iMovie HD. The system is not seeing the DAC on the fire wire bus. I have tried new cables, plugging into a native bus etc etc. but no go. The DAC is admitted 5 years old but worked perfectly up to now. I am loath to have to scrap it because of a Fire wire incompatibility issue. Anyone else out here with similiar issues and a possible solution - or else off to the mail-order I go and cough up €200 😟