Vista - Ultimate x64 install: CD/DVD driver or SATA driver?

Trying to install Ultimate x64 on custom build:

XFX 790i Ultra SLI
Intel Core 2 Quad 2.5GHz
Patriot 2x2GB DDR3 1333MHz
WD Raptor 150GB 10,000RPM (clean)

System is able to boot from DVD..I get to "Install Now" part then get an error message along the lines of 'a required CD/DVD drive device driver is missing. Find it and load it'

I've looked around for the past two days at various solutions and none have worked..I tried:

switching CD drive from master to slave, changing IDE cable, removing 1 of the RAM sticks, switching CD drives from brand new to older and tried both as master/slave (new is LG super multi, old is Sony combo), changing SATA cable, changing SATA port, loading Vista x64 drivers from 'IDE' subfolder of MB driver download on USB flash drive (Vista install didn't even find any drivers)

Both CD/DVD drives I tried are PnP and have updated firmware so I tried the HDD driver route but to no avail. So I'm at a loss.

Anybody know something I don't?