This is my first time working with Ubuntu (or Linux), so please be patient.

I am running Ubuntu 12.04-powerpc "Precise Pangolin" on a Mac PowerBook G4 with 1.67GHz processor.

The firmware/driver for the wifi card is missing. For reasons not worth explaining, I cannot physically plug the computer into the network. I have another computer, a MacBook Pro running OSX, from which I can download files and port them by USB thumb drive.

The wifi card in the PowerBook G4 is by Broadcom. The chip is BCM4306, rev. 3. The PCI number is 14e4:4302.

I have downloaded b43-fwcutter_015-14_powerpc.deb and dropped it into the Home folder on the Ubuntu machine. However, it will not install. When I double-click, it opens with Ubuntu SoftwareCenter, but the "Install" button is inactive: I can't click it. There's a message beside the inactive button saying, "An older version of 'b43-fwcutter' is available in your normal software channels. Only install this file if you trust the origin." If I "right-click" the .deb file and open with Archive Manager, it shows me the "DEBIAN" and "usr" folders, but I'm unsure what to do from there...and fairly certain this is not the right way to do things.

Maybe I have the wrong version of b43-fwcutter for my machine/version of Ubuntu?

The documentation for this problem is a mess. It refers to all sorts of out-of-date Ubuntu versions and to an array of different "cutter" and firmware files. Maybe I'd be able to figure this out if I were a more seasoned Ubuntu user, but I have no idea why Sofware Center won't let me do the install. I would be VERY grateful for an explanation of how to get the wifi card working on this machine again. Thank you!