I am not sure how madwifi works as I have not used it, but the way ndiswrapper
works is that it adds a Windows api that must be loaded each time you boot the
computer. This means that after getting it to work you need to change settings
so the ndiswrapper module loads with your Linux distro at boot time. This means
that you need to take a few extra steps after you get it working. In
ndiswrapper, you can do it from the commandline using chmod and editing a file
or you can use the GUI tool ndisgtk which takes care of the details for you.

If madwifi is not working, you may have to re-install it and check to see if
there are any steps that you left out so the changes are permanent, ie. maybe
madwifi needs to be loaded at boot up. This is only one possibility. Someone who
has used madwifi may be able to provide more useful help.