Just to get it posted here, here is the solution for a similar-sounding issue that seems to affect some Windows 7 machines. This solution is pulled from the discussion link above:
"I had the same error in with the i-tunes installation and i did this and it worked… This works for any i tunes that fails to install itself on 64 Bit
You have to go into your registry.
Start, run, type in “regedit”.
Next go to HKEY_LOCAL_MACHINE.
To the right you’ll see WOW64. Double click on it, or right click on it and click on modify. Change the setting from 1 to 0.
Next, go to the start menu again and type in the search box: “services.msc”.
Look for and find the Windows Installer service.
Double click on it and tell it to stop. Next, tell it to start.
You should now be able to install your programs."
So this is the first thing we’d try, in looking to get that driver install working.