Adding 2nd Optical Drive into Mac Pro (first gen) makes both unusable!

Hey all,

I recently purchased a second DVD drive to go into my first gen Mac Pro 2.66Ghz.

The installation went a little rough, although OK in the end. The IDE cable seemed reluctant to want to stay in a safe place.

Upon booting however, and now had no optical drives installed!

Even System Profiler reported no disc burning capabilities except my external USB CD Burner.

I've taken the second Optical Drive out, which by the way was one of these: http://eshop.macsales.com/item/Samsung/SHS202NBLS/

My original Sony (Disguised NEC drive) drive is now working again, although what on earth happened?

Should I try swapping the drives around? E.g the Sony on the bottom and Samsung on top?

Any thoughts would be appreciated,
Thanks,