Cause

When attempting to eject a CD-ROM on a Ultra 450 system, the eject cdrom command fails, displaying the error message.

This is because the CD-ROM is on controller 1 not 0. For the eject(1) command, the cdrom "nickname" equates to /dev/rdsk/c0t6d0s2. On an Ultra 450, the CD-ROM is /dev/rdsk/c1t6d0s2. So, using cdrom does not work.