I'm installing 6.1 on a dual PII-133 which has no IDE hard drives but 2 SCSI drives. Using the normal setup, I noticed an error about not being able to access /dev/hda. I selected "skip disk" and the installation went right to the end without further complaint. When I rebooted, I got the message "missing operating system" from the bios and progress ceased. I finally had to go to a custom installation in order to tell setup that I needed LILO to be installed on the first SCSI disk. Seems like normal setup should have realized that the hda was not there and put LILO on the SCSI disk or at least posted a message saying to use the custom setup.
This issue is resolved in the latest beta installer.