> However, dhclient wlan0 keeps retrying and never succeeds. I know the
> access point is properly configured, because it works for this USB device
> under WinXP.
You should check dmesg or your system log for zd1211 related messages.
You need to be associated first before dhclient can get an IP.
If you are associated, try a static IP to see if that works.
If your logs don't show some kind of association message, you haven't got a
wireless connection. You need to double check your wireless setttings. You
could do 'iwlist wlan0 scan' to see what parameters are exposed by your AP.
Maybe you can spot a mismatch with your client settings.
Zd1211-devs mailing list - http://zd1211.ath.cx/