Sorry Dave, I'm stumped.
That card reader should be supported by Win Xp.
See http://www.e-shop.com.au/47196-vbm6028.htm
Try to borrow another recent vintage card reader to see if it works OK.
If YES, your card may be faulty.
If NO, it may be an issue with Xp.
You may try visiting Microsoft Knowledge Base for a remedy.
Bob