Okay, is it a problem to put them both on the same cable? simply set the jumpers accordingly (mast/slave, not CS), and it wont matter which order they're in, although I am assuming that the CD drive will be on the end of cable.
Make them both on cable IDE 0, or IDE 1.
Forget about the other cable, If this works, at least we know it is not a drive problem.
If you feel it is imperative for you to have them on seperate cables, then switch the cable out, and do the same thing with the other cbale, to make sure they both still work. THEN put them on their own cable each, and at this point, the jumpers shouldn't matter. Simply the Hard drive should be on the IDE 0, and CD on IDE 1. (Unless your IDE's are numbered 1 & 2.).
Hope this helps.