firstly, mysql, perl and apache (the webserver) are more than likely all installed already. you can check by going to add / remove packages, and checking if perl, httpd and mysql is installed. Then, as root, run redhat-config-services, and check that they are all started and will run automatically. Installing bugzilla is quite a process, the best advice i can give after this is to follow the instructions on the site as far as you can, and post again where you get stuck. It's a waste repeating everything here in a post if it's already on http://www.bugzilla.org/docs/html/in...-bugzilla.html
To get the bugzilla tarball, go to http://www.bugzilla.org/download.html.
See how far you can possibly get, then post your problems