I've never had any experience with Debian, and therefore don't know how much help I can be to you. Are you sure that "boot cd" is a valid command? When I install RedHat, for example, I just set the BIOS up to run from the cd, as the disks are bootable.
Perhaps you have to mount the cd first? (e.g. mount /dev/cdrom) ??
I'm unfortunately in a lot of pain right now (just had major surgery on Tuesday) but I'll check around for you on Debian installs, and get back to ya within a day or so. Good luck in the mean time!