bill - 6:07 am on Dec 7, 2003 (gmt 0)
I've seen this on some XP machines. Sometimes you can get around it by connecting to a visible SSID and then turning the SSID off. If you have trouble connecting again it sometimes helps to reenable the SSID broadcast for a few minutes.
apparently there's a bug that affects some systems - they won't connect to an access point with a hidden SSID.