Everyone seems to be having similar problems. When trying to get your camcorders going you should.
1. Make sure that you have your cards seated and screwed in tightly.
2. Load all appropriate drivers, go to the windows or manufactureers web-sites and make sure you are current.
3. Make sure that the camera is off. Attach the firewire to the camera.
4. Attach the firewire to the PC.
5. Do not start your editing program yet.
6. Turn on your camera and wait for the OS to recognize and load the appropriate device. DV IN on your camcorder doesn't mean you have a successful conection to the PC. It just means that the camcorder sees the cable is plugged into the camera.
7. If the Digital device dialog window pops up, click on the appropriate program link. I always click take no action and then load the program.
8. If you do not get the device loaded, go to start/my computer/control panel/system and click on hardware device manager. Click on any of the listings, then click on the scan for new hardware icon of menu pull down.
9. If the camera is not added, or has a problem, try to reload the drivers.
10. You can always try adding the device under the scanners and camera section of the control panel menu.
11. Are you using an external firewire drive? It should be on a separate PCI firewire card. I haven't seen a camera that will cooperate with a drive on the same card yet, even with 3-5 jacks.

Good luck.