Update Website Coded in php and mysql in 2002

General information for the website: NASCAR Fan Discussion Site
Kind of development: Customization of existing website
Description of requirements/features: We're looking for a Web Developer to upgrade existing website custom coded back in 2001 or 2002 in php and mysql. The site is currently running on php 4.4.9 and mysql 4.1.22-standard. I am upgrading the server and we need the existing site code updated to modern, clean, modular, robust code that will operate on latest php5, latest mysql5 and latest apache cPanel server. Of course it doesn't have to stay php, we are open to recommendations on any language and open to any input. We are looking to keep the design the same but upgrade the code for the public facing website and the admin section.
CMS and Admin requirements: Update coding for entire admin section
Extra notes:
The live website is racerap.com.

The test website is racerap1.com. (I transferred the complete site to a VPS running php 5.4.26 and mysql 5.5.35-cll located at racerap1.com.) You will see it gives a blank page and doesn't work on php5 and/or mysql5.

UPDATE: Due to many questions on the admin section:

The admin section has:

messages are placed in a queue to be approved unless the poster is a paid member. The admin can approve the message or delete it. It also has an ad management system where the banner ads and side ads can be managed and posted. People can request handles (membership) and it's managed in admin. Sessions can be cleared. I am attaching a screenshot of the menu in admin section. Not all features are used and they won't be kept. Just have not finalized that yet.

Also, the entire site code has to be updated. I don't mind changing to any platform as long as it functions exactly the same as it does now.