Is the make of the firewire card canopus?
What I am saying is you maybe want a generic firewire card - nothing to do with video, a regular PC firewire card. Maybe the canopus one does something different and thus there is an incompatibility?

I use the onboard firewire port on my motherboard or a cheapo firewire PCI card I picked up, depending on which machine I use. I use that with the capture built into premiere and it works fine.