SOS failure on mkisofs on FreeBSD-6.1-R amd64

[luizbcampos at gmail.com]

       Trying to make a bootable CD, I did the following according to
FreeBSD doc:

       #mkisofs -R -no-emul-boot -b /boot/cdboot -o /home/user/0S to
be burned  /home/user/cdboot


       And I got the message: "uh, oh I can't find the boot image /boot/cdboot"

       Suggestions?