Hey OP, sorry you're having trouble! I haven't rooted my Atrix yet (and can't right now either, kinda busy but will tonight), but I think it will be much easier than you seem to be expecting... the rooting instructions for all other android devices I used had all these required drivers, programs, etc, but you should be good to go without having any of that stuff anyway.
just plug in your atrix over usb, turn on usb debugging (settings > apps > development), pull down the notification bar (the white bar at top that has time, signal, battery, etc), and you should see something about the usb connected... press that, hit mount, and if the option pops up anywhere, select "mass storage"
hope that helps - I'll give you a better rundown tonight, if you need it.