if (!class_exists('fud_user_reg')) {
	fud_use('users_reg.inc');
}
$fudUser = new fud_user_reg;
//code to get get $fudforum_id and $cur_ses_id
$fudUser->user_login($fudforum_id, $cur_ses_id, true);

Call to undefined method fud_user_reg::user_login()

// get $fudforum_id. Confirmed to be valid
$cur_ses_id = get_cur_ses_id($fudforum_id);
user_login($fudforum_id, $cur_ses_id, true);
 
function get_cur_ses_id($id) {
	$fudSesId = $_COOKIE[$GLOBALS['COOKIE_NAME']] or 0;
	if (empty($fudSesId)) {
		$s = db_saq('SELECT ses_id, sys_id FROM '. $GLOBALS['DBHOST_TBL_PREFIX'] .'ses WHERE user_id = ' . $id);
		if (!empty($s)) {
			$fudSesId = $s[0];
		} else {
			$fudSesId = 0;
		}
	}
	return $fudSesId;
}