OK, but that's your login script, right? You need to do something to get the lastactivity updated when they "doing something" (by which I assume you mean accessing other external pages?). You probably only need to do something like:
PHP Code:
define('START_CWD','/home/pzone/public_html');
define('CWD','/home/pzone/public_html/forum');
chdir(CWD);
include_once CWD.'/includes/class_hook.php';
include_once CWD.'/global.php';
exec_shut_down();
chdir(START_CWD);
on each of your external pages.