hardware browser and mounting scsi cdroms

[hawkwynd]

Working on my scsi cdrom tower, I have 7 CDROM drives running off the 
Adaptec aha152x controller. The hardware browser lists all 7 drives, 
labeled /dev/scd1 - /dev/scd7

My problem is drives 5,6 and 7 are not able to be mounted,  when using 
the disk manager to mount the drives,  I receive:

   /dev/scd5 : unknown device

Same error for drives 5-7

Drives 1-4 will mount without a problem.

Any thoughts?

Thank you,
Scott Fleming