Please try following:

Open UnitControl! Can you see it here?

If not: Go to Open Firmware, insert a CD and enter following:

>eject CD
or
>eject ide1 (if CD-drive is set as slave)

If CD is ejected, your drive is recognized by firmware and we have to look why MOS doesn't.
If not you really may have a problem with your cable or plugs (data and/or power)

Edit FYI:
There may be no definition (devalias) for ide1 in OF of your PB. In normal case your HD is .../disk@0 and CD-Drive is .../disk@1 (other PB may be have different settings). In that case eject ide1 won't work.
Some CD-drives can be set as Master or Slave. My experience is, that this makes on most Power-Apples (witch have Open Firmware), no difference to which it is set, but not on all! On one PB OF had troubles to find such a drive. Astonishingly OSX and MOS find it - but only after system is booted up - it was not possible to boot from that drive. After setting it to SLAVE it runs normal.....maybe your problem is similar...