I am posting this because if it helps mitigate at least one person's frustration, then it will be worth my time writing it.
I have an IBM ThinkPad T42p which is only 4 months old. I constantly update both Windows XP SP2 and the IBM software with weekly updates / patches . In other words, its kept very current. When I purchased the laptop I also bought what I thought was a compatible FireWire PCI cardbus to use when I did get a digital camcorder.
Well, recently I purchased a CANON Elura 90 DV camcorder and tried to connect to the laptop via the FireWire / PCI cardbus (SIIG 1394 2-port cardbus - product # nn-pc2012). No matter what I did, I could not get the computer to recognize the camcorder. I was getting an error on the 1394 Net Adapter. No one could help me at IBM or SIIG (you can't CALL SIIG, you have to email them and they never got back to me), nor could anyone help me at the local computer superstores. Finally, after exhaustive research on the Web, I found a SIIG support release stating that this particular card does not play well with XP. Doh! Why then did IBM sell me a product that was a crap shoot on whether it would work or not?
This very obscure SIIG release went on to state that it may help to disable the PCI Power Managment in the BIOS. I did, and the cardbus works fine now. Amazing!
So if anyone finds themselves with this situation, please go to the BIOS user interface (F1 on boot on IBMs) and change the PCI Power Management from automatic to disable. It may not work for everyone, but it worked for me. I wish this post would have existed when I was researching the problem.
For what its worth.