http://ubuntuforums.org/showpost.php?p=3218583&postcount=7
and
http://www.linuxforums.org/forum/ubuntu-help/110112-ndiswrapper-installation-issues.html
You must have your wireless card driver installed into the kernel.
If you have an intel 3945, you should install via synaptic the daemon, the firmware, and the source of ipw3945, close synaptic, and then, do a "m-a a-i ipw3945-source", which will produce the module to plug into the kernel, and then do a modprobe ipw3945.
Something from the Ubuntu Forums that might help wireless woes
Hello