This same problem just started happening for me a couple days ago and in my search to fix it, I found a post this morning on ubuntuforums.org with an alternative fix. Since I haven't seen any mention of this method yet here, I figured i go ahead and post it for everyone else.
Here's HalfNote5's original post:
Since I lack enough reputation to post the screenshot here, I've went ahead and copied the text instead.
12.04 and ndiswrapper modprode "FATAL: Module ndiswrapper not found"
Just a heads up for people with ndiswrapper problems (I crawled the
Ubuntu forum and didn't really find this; the info was aggregated from
several other sites.)
If you're using an older version of ndiswrapper, and you have the gui
AND the program interface (and ndiswrapper even shows that the
hardware is attached) but when you modprobe, you're getting this:
FATAL: Module ndiswrapper not found
It means you need to install
(And of course, install ndiswrapper-utils-1.9)
None of which appear to be "Dependencies" for ndiswrapper, but without
which it simply does not work.
Apologies if this is already posted somewhere, but when I was looking
for it, I saw several people asking, but no definitive answers.
P.S. My install was Xubuntu Alternate. Your experience may vary. ; )
Last edited by HalfNote5; May 26th, 2012 at 09:13 AM.. Reason: slight correction
Link to HalfNote5's Original Post
Since I use Ubuntu 12.04 LTS as my OS, I just searched each installs name in the Ubuntu Software Center program and installed each one.
After everything finished installing, I reopened ndiswrapper, then removed and reinstalled the wireless driver.
Ever since then, my wireless adapter has working perfectly.
I hope my answer helps make this fix easier, even if just a little, for others with this same problem in the future.