Turning main.php into a function

The script works well when ran on its own. But I have been trying to simply copy and paste the entire main.php into my own php file as a function to be called from my main. When I test this function I get "Fatal error: Call to a member function addActiveGuest() on a non-object in C:\wamp\www\include\classes\session.php on line 60". Any idea why?

Maybe I wasn't clear enough. With the database installed and all scripts unmodified it works great. But if I try to turn main.php into a function with

Code:


<?php

function login() {

     // main.php in its entirety unmodified

     }

login()


and run this script I get an "Call to a member function addActiveGuest() on a non-object in C:\wamp\www\include\classes\session.php on line 60" error. I'm baffled as to why. Please help.