Don't install that driver.
W7 has it's own AHCI driver native. You do not need to preload any driver during installation like we did with Windows XP. You just set AHCI in BIOS and that's it.
After you start the installation DVD, go into advanced setup, and format the hard drive to erase everything you did previously, then try the installation again, just letting W7 do it's thing.
After W7 is installed then you can go in and install the manufacturer's AHCI driver, or Intel's Rapid Storage driver.