If the pirate's solution did not fix it,..
Make sure you plug the firewire drive into the USB/Firewire port on your motherboard. I had a similar problem, and it was because I was using the PCI card, and not the USB on the board (hence not enough power).
PCI cards sometimes do not have enough power to operate a ext. HD and you will either need to use the power supply that comes with them, or make sure you use the USB/Firewire onboard your motherboard.
