Debugging Help Needed

I'm not a PHP coder, but I have an application written in PHP (CMS Made Simple) that stopped working when I upgraded postgres to 9.x. I seem to have most of the problems fixed (those with adodb_lite) but now need to track down why I get a "404 Page Not Found" error when I try to invoke the local application. BTW, I'm running php-5.2.17 on Slackware-13.1. Running 'php index.php' from the application subdirectory to the document root directory, I learn the code to search in the directory structure. It turns out to be misc.functions.php, and the specific function in that file is ErrorHandler404(). However, I have not been able to trace execution to learn just where this function is being called. Looking at the PHP manual I see there's a function called debug_print_backtrace(), but I have not found how to properly use it. When I insert it at the top of ErrorHandler404(), php throws an error when I try to run index.php: function ErrorHandler404() { debug_print_backtrace()

        #if ($errno == E_USER_WARNING) {
                @ob_end_clean();
                header("HTTP/1.0 404 Not Found");
                header("Status: 404 Not Found");
                echo '<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">

<html><head> <title>404 Not Found</title> </head><body> produces: PHP Parse error: syntax error, unexpected '@' in /var/www/htdocs/cmsms/lib/misc.functions.php on line 223 How can I determine where ErrorHandler404() is being called so I can fix the problem and get the application running again? Rich