Installed, but not working

Hi, I recently had a script installed on my website (Adult 18+ site. The site’s broken at the moment, but when fixed it will link to pornography. Please keep this in mind).

This happened months ago when I tried installing it myself, and now again as the script’s new owner helped me with installation. Either way, this error comes up:

[php]Warning: preg_replace_callback() [function.preg-replace-callback]: Requires argument 2, ‘page_builder’, to be a valid callback in /home/siliconelover/ on line 143[/php]

The guy I’m talking to claims that everything is set up correctly and that I should contact my host regarding what’s preventing it from working. Anybody know?