I had this same problem just 2 days ago, heres what I did to fix it:
Go to /etc/pcmcia and edit the file named "config" (I used vi).
If you do a search for the manfid of the AmbiCom card as reported by "cardctl -ident", you may find that a card or two from different manufacturers use the same manfid strings. Comment out the entries that have the same strings as your card (mine was 0xd601, 0x0002)
Now, edit /etc/pcmcia/wlan-ng.conf and perform the same search, again commenting out any cards that share the same manfid string as your card.
Finally you will need to add an entry for your card in wlan-ng.conf like this:
card "AmbiCom W1100C 802.11b CF-Card 2.2"
manfid 0xd601, 0x0002
bind "prism2_cs"
right after any "device" declarations (my wlan-ng.conf only had one)
NOTE: Do NOT just type in the manfid string that I have shown here! You should run "cardctl -ident" to find out what the manfid or your card is. It may be the same, or it may be different depending on which model card you have.
Hope this helps end your frustration
Cheers,
John