Hi, I got the same error on linksys wusb12 device as well. README file on
www.linux-wlan.com asks you to ignore the error. and suggects that you run *certain* commands to make it work. I ran and it worked..... here are the comments from README file refer to the latest for accurate information....
--------------
FOR USB USERS:
A) Make sure your kernel usb support is running
B) Plug in the Prism2.x USB device
C) Run 'modprobe prism2_usb prism2_doreset=1' to load the driver into memory.
D) Run 'wlanctl-ng wlan0 lnxreq_ifstate ifstate=enable' to initialize the
driver+MAC functions.
E) Run 'wlanctl-ng wlan0 lnxreq_autojoin ssid=<your ssid> authtype=opensystem'
to enable the MAC in Infrastructure Station mode.
F) Run 'ifconfig wlan0 <your IP address>'
-----------------
I replaced the last command with 'ifup wlan0' to pick up my dhcp settings. It works great now!