Also, the same for all the INF files for this other driver I just tried

Are you in the same directory as your .inf file? Do ndiswrapper -l, remove any drivers listed ie ndiswrapper -e xxxx, then do ndiswrapper -i /path-to/bcmwl5.inf bearing in mind its case sensitive so if its BCMWL5.inf install it like that. Also make sure you have all the files from the driver package in the same directory.

Hadn't known it was case sensitive, though I've been treating it as such for the most part. Thanks a lot ^_^ I got the driver installed fine.
Now, still using the Installation Wiki, under the Load Module section, it doesn't specify how to handle errors. depmod -a got me no errors, but this is what happened with modprobe ndiswrapper:
So, what's wrong now?

No, got me now. Maybe a case of trying another version of ndiswrapper, not sure. If you want to compile your own version try linking /usr/src/linux-2.6.12-12mdk to /lib/modules/2.6.12-12mdk/build as earlier in thread and remove existing ndiswrapper, unless someone can help with specific broadcom advice.
Edit: of course maybe some vital bits missing from cd3 that we dont know about!

Are you sure it didn't unzip to another directory (within the one you unzipped the archive from)?

Beagle: I was trying to compile it myself before, and I kept running into problems creating that link, because the directories aren't there.
Nylex, I'm a little confused. I'm pretty sure I didn't, because there was no need to unzip twice. I think the problem goes back to the fact that I'm still missing the directory /lib/modules/2.6.12mdk (as well as /usr/src/linux-2.6.12mdk).
Maybe I should just keep downloading and burning disk 3 and reinstall Mandriva altogether until it works? I have to get this up and working by Tuesday or I have to switch back to Windows.

What I meant was, when you unzipped the archive, it might have created a directory, but since you got the driver installed now that doesn't matter. Why do you have to switch back to Windows?? :/

I absolutely have to have Internet access, and I know I can do that on Windows. I'll be dual-booting of course, until I can get it all worked out. I love Linux too much now to go back to Windows permanently.

That's fair enough. I dual boot, mainly so I can play games .

Yeah, maybe you still need the kernel source, I'm not familiar with Mandriva though.

Probably quicker in the long run to try to re-install - one thing to confirm is whats in /usr/src/ and /lib/modules/. linux-2.6.12-12mdk is what you should be looking for not 2.6.12mdk or linux-2.6.12mdk. If you havent already re-installed do ls /usr/src/ and ls /lib/modules/ . One good thing about all this is you're learning stuff that will come in handy later on :-)

Yeah, I figured that stuff out heh. I felt so stupid when I realised... Anyway, I got everything up and running just fine, so thank you all so much for helping.

Good to hear .

You might be able to run the driver executable in wine to extract the drivers.