Many users have experienced issues with FireWire devices not working with Win7-64. Often, those same devices worked with their previous OS, but not now. The cameras are not being recognized, or their other FireWire devices are just not being seen.
This appears to be related to the IEEE-1394 FireWire driver that Win7-64 installs by default, at least in most cases.
The "fix" is to go to Device Management, and locate the driver used for FireWire. One would replace that default driver with the one with the word "Legacy" in its name. Fairly simple to do, and it fixes FireWire/IEEE-1394 issues for most users.
* Click Windows Start orb; type "device manager" into the Search box and select Device Manager (or launch Device Manager anyway you like)
* Swivel open the "IEEE 1394 Bus host controllers" item
* Right-click on your listed 1394 controller; select "Update Driver Software"
* Click the "Browse my computer for driver software" button, followed by the "Let me pick from a list" button
* Select the option that has "(Legacy)" at the end of the name; click Next and let the driver be installed
* Close out of dialogs and retry capture