Problem installing on Asus P5B Deluxe?

I have a machine built with an Asus P5B Deluxe motherboard. I have a 400GB
SATA disk and an IDE DVD-burner.

When I try to run setup off the Vista DVD, it boots the installaton with
problem and I can select the initial installation options. But, after
clicking on "Install Now" in the next setup screen, I get the following
error: ""A required CD/DVD drive device driver is missing" a nd I'm prompted
to provide a driver. I have not been able to get past this.

Both the SATA disk and the DVD-ROM controllers in the BIOS are set to
"IDE-mode". I have no problem installing Windows XP or Windows Server 2003
on this machine without providin any driver during setup.

What could be the problem?

Olav