The ref guide on pp 62--64 discusses making a rescue disk, which requires a root fs image on a 2nd floppy. This is supposed to be (according to the manual) on the cd-rom under /images. It's not there -- and not on the RedHat ftp site, so far as I can tell. Lack of a working rescue disk set has turned out to be a major hassle!
We have changed the way in which rescue mode operates in release 6.1. Now all you need in order to access rescue mode is the install media (be it the cdrom or the boot disks that you used to start the installer) Just boot from those and procedd as you did when you first installed. Instead of the installer going into its second stage (where you get the welcome screen) it will drop you at a shell prompt where you will be able to access the features of rescue mode.