Man, I would love to know the answer to this too.
I can't find any form of Bootcamp installed on my iMac i7, and the updater does nothing when I try to launch it.
Although, with the problems some late 09 iMacs are having with this, I may just be better off. I have a gaming keyboard/mouse anyway, so don't need the fixes : )
I feel like an idiot. I don't know how I did it, but I was running Windows 7 without the full Bootcamp install. I reinstalled 3.0, then without restarted, ran the patch to 3.1. Everything works perfectly.