Hi and welcome back!
Try changing the encryption protocol on the AP you're trying to connect to (WPA2, WPA, WEP and/or none) and see if it makes any difference. From what I have read, for some users the AmbiCom WL1100C supported WEP only, for others WPA too, it might depend on the revision of the firmware installed on the card.
Have you ever managed to successfully connect to a network in the past using that card? On the same AP, with the same, or different ROMs? Have you tried connecting to other APs, too?
Varti