Just a post for anyone that finds this issue and possibly for someone in the dev community to fix.
I was having problems getting the windows drivers for smoothieware to work on a Win7 Ultimate x64 build.
Turns out the 1.1 driver inf file has a missing line in the vista 64 section as follows:
usbser.sys,0x20
If you add this to the smoothiware.inf file the driver should install fine.
It’s my undertsanding you shouldn’t need to open/worry about the driver file’s content, you should just follow the instructions at http://smoothieware.org/windows-drivers , if you are looking at the inside of the file, you are not following instructions and should move back to following the documentation.