1394 firewire pci card problem

Hi guys, I have just purchased a couple of pci 1394 firewire cards.I installed one in my pc which is running win XP and service pack 2.
The host controller installed correctly but there is an exclamation mark against the adaptor setting. the error message says this device cannot start.
I tried the other card just in case the first one was faulty but got the same result.
I also tried this on my sons pc which also has XP and service pack 2 this also gave the same problem.
Any help much appreciated as this is driving me nuts.
thanks
Alan