There is an issue with recent 2.6 kernels and some ATA/SATA controllers which I have run into while trying to install both CentOS 5 and Kubuntu 7.10 (Gutsy Gibbon). Initially, even the boot CD would not work from the builtin DVD reader. To boot the first time I used an external USB DVD.
The relevant error was "failed to set xfermode".
See http://fak3r.com/2007/06/22/failed-to-set-xfermode-solved/ for more info.

Essentially you need to add irqpoll to the linux boot line. You can do this, after install, by editing /boot/grub/menu.lst and adding irqpoll to the #defoptions line. At the the end of the install process before rebooting open a terminal and do a "chroot /target /bin/sh". Then cd to /boot/grub and edit menu.lst.

If you do not have a USB cdrom available see this post about passing kernel options to grub on boot:

http://www.redhatmagazine.com/2007/03/21/using-grub-to-overcome-boot-problems/

Since I had a USB drive available I did not have to do this.