Again. Snow Leopard, 4-9 pin firewire connection to firewire miniDV camera, no go. I'm believing Apple has an issue.
First thing to check is that the camera is even being seen. Open System Profiler in the Applications/Utilities folder, connect and turn on the camera, look in the Firewire entry under Hardware.
If you have a way to prove your camera and cable are working properly, send Apple a bug report.