And, be sure to connect in the following sequence:
With the camera off, plug in the cable on the camera end, then plug in the cable on the computer end, then turn on the camera, which the computer should detect automatically.
Firewire comes in two flavors: four-pin and six-pin. Make sure that you have the proper pinouts to match the connectors on each end. Also, don't exceed 16' in cable length (don't know why you might want to, anyway) to avoid signal degradation.