[TigerC10]

Well, changing the working directory generally only messes up other includes... I don't see anything in your code that would cause that problem. If you think it's a problem, you can try this:

<?php  

// ####################### SET PHP ENVIRONMENT ###########################  
error_reporting(E_ALL & ~E_NOTICE);  

// #################### DEFINE IMPORTANT CONSTANTS #######################  
define('NO_REGISTER_GLOBALS', 1);  
define('THIS_SCRIPT', 'Chat'); // change this depending on your filename  

// ################### PRE-CACHE TEMPLATES AND DATA ######################  
// get special phrase groups  
$phrasegroups = array(  

);  

// get special data templates from the datastore  
$specialtemplates = array(  
      
);  

// pre-cache templates used by all actions  
$globaltemplates = array(  
    'Chat',  
);  

// pre-cache templates used by specific actions  
$actiontemplates = array(  

);  

// ######################### REQUIRE BACK-END ############################ 
$curr_dir = getcwd();
chdir('/path/to/bbs/directory');   
require_once('/path/to/bbs/directory/global.php'); 
chdir( $curr_dir );

// #######################################################################  
// ######################## START MAIN SCRIPT ############################  
// #######################################################################  

$navbits = array();  
$navbits["chat.php"] = 'Chat Page';  

$navbits = construct_navbits($navbits);  
eval('print_output("' . fetch_template('Chat') . '");'); 
?>

Although I have a question... Why are you defining NO_REGISTER_GLOBALS to true? Doesn't that stop you from accessing the global variables? What happens if you define it to false instead?