One of the following may help you solve your problem:
1) Ensure that your CD-ROM drive is turned on & plugged into an
active electrical outlet.
2) Ensure the CD-ROM drive's SCSI connection is properly connected to
your Macintosh (see your CD-ROM drive's manual for instructions).
3) Ensure the CD-ROM drive's SCSI ID does not conflict with another
SCSI device's ID number (consult your CD-ROM drive's manual for
further information).
4) Ensure all CD-ROM drivers are installed.
5) Ensure the CD-ROM drive has been turned on before the Macintosh
has been turned on (with the CD-ROM Player turned on restart your
Macintosh).
6) Try to use another CD-ROM. This will narrow down the problem to
either the set-up or the CD-ROM disc. It is highly unlikely that
the problem involves the disc.