After researching this problem at: http://forums.photographyreview.com/...9&page=2&pp=25
I have found this forum staing this.
1.)Assuming you have service pack 2 installed ...
Go to your control panel. Select the "security center" icon. Turn your windows firewall OFF.
Windows was treating your firewire connection like a network connection and automatically firewalled itself when you installed the service pack. You can fix the problem on the firewire connection only by going to Start/Control panel/Network connections and then right clicking on the firewire, 1394 connection. Then left click on properties, the advanced tab and uncheck the protect my computer button. That will take the firewall off of just the firewire if you want to keep your network connection safe.
They are stating at the post that this is the problem. Notice they are talking about 1394 connections.
Here is a Microsoft site with a patch stating that "After you install Windows XP Service Pack 2, some 1394 devices (such as digital cameras that use S400 speed) may not perform as expected".
I also read that people having this problem with SP1 that upgraded to SP2 no longer had a problem.