Whenever I try to go to setup, it just keeps coming up with this error, even if I run as admin, the same thing still happens. I've even unpacked it, same problem still happens.

"This program installs Jazz Jackrabbit 2 version 1.00h.

A newer version of Jazz jackrabbit 2 is already installed on your computer. You cannot replace it with Jazz Jackrabbit version 1.00h.

Install will now exit"

Yes, I do have 1.23 and 1.24 installed on my comp...would that mean I'd have to go through the trouble of uninstalling them just to play some prototype?