Hi, CeCeMacster - welcome to the Discussions!
You might check your optical drive jumper settings to insure that it's set as Master. The Zip drive should be set for slave if it's on the same cable.
Actually, a hard drive may be installed along with the optical drive on that slow ATA-3 bus and you weren't off the mark at all with your attempt to do so.
I'd recommend that you initiate a new thread
here, where the members can better advise you with your specific issue, particularly since this thread deals with a somewhat different issue. You might simply copy/paste your entire post to the new thread.
Gary