It could be the firewirecard which is causing problems as well.
Connect the camera, before you start your pc. If the pc is started does Windows see the camera ? if not, this is the first problem to tackle. If Windows won’t properly see the camera, Liquid won’t do it at all.
This kind of problems can come from a resource conflict.
Try putting the Firewire card in another pci slot. Try them all !!And see if it makes a difference. Disconnect all external devices when you do so (USB, Network, etc…).