By Definition, the 802.11b standard says that these items are compatible with no encryption, and with 64bit or less encryption. The previous poster was correct, and I recently had the same exact issue, but with a 3com card (the top o the line one with the XJack and all). I learned (the hard way) that there are several issues which can screw up your ability to associate with a wireless acess point:
1)
The SSID a.k.a. ESSID a.k.a. WLAN Service Area. While some cards have the ability to scan for all available (ANY), this may not always work correctly. Make sure these settings are the same in the card as in the Access Point.
2)
The Channel: Again, most cards can search for an available one, but if you can set this manually, do so just to get the thing working.
3)
Security Settings: I think for now you should disable these on the access point and on the card.
Some other things to check:
Short vs Long Preamble: Some cards can only do one or the other. If you cannot find a setting for this on the card, look at your router settings under advanced\wireless and see which one you have set. Try the other one!
And Last but most certainly not least....
During my travails with Linksys and 3Com technical wait... um... er... I mean support, I had to download the latest drivers and patches, firmware for both my router and my card (gulp) and the item that finally did the trick was installing service patch 2 for windows 2000 professional on my laptop. For some reason, the original windows configuration was not allowing me associate with the wireless access point.
AN ironic side note: I got the 3com card because of reported difficulties on this board with the linksys cards combined with the Linksys router. It would seem I was destined for trouble the moment I decided to go wireless....
Good Luck!!!