Ok. Lets backup one sec. You said these same cds boot in the 8600. But can you maybe pull the CD-ROM drive from the 8600 for use in the IIci? Its not clear, but it sounds like you did not - simply that you have some of the same model drives.

I only suggest this because old model cd-roms are very touchy when it comes to CD-R media. And while the models may be the same, the brand or even the brand of the eye may not be the same. So if it works in the 8600, that exact drive may be key. If you were not using CD-R, there may not even have been an issue. Also I would leave the jumpers in place if you pull it.