Actually, it's time to apologise...
I have two DT366's, both were running Puppy Linux just fine, although WPA2 wireless was a pain in the butt to get working. I don't mind puppy at all, but it still seems a bit "clunky" on the DT's hardware. So I thought I might try XP just for looksies and I installed it on my other DT366 but found the 500MB internal space too limiting, so that's when I bought some 16GB CF cards. When I inserted a card in the DT366 running Puppy, there were no problems, but the XP had the problems I mentioned earlier.
Last night I swapped images and XP now installs the PCI CARDBUS driver with no issues on the other 366 and all is working fine. So I have to put it down to a hardware problem for the moment on one of the 366's. It's not surprising as I've had that particular 366 apart and back together many time whilst I've been poking around it, which was also why I chose that one to try XP.
XP seems to be much snappier on the DT366 than Puppy. Another reason I wanted to try XP is that I'm using this 366 on the road in my vehicle with a heap of Ham Radio equipment and quite a bit of amateur software is only written for Windows.
Sorry for the false call and thanks for (yet again!) pointing a lost soul in the right direction!