View file signup/setup.php

<?php 
class Smarty_Signup extends PxPSmarty {
    function __construct($app = ''){
        global $theme,$config;
        $site_url = $config['site_url'];

        parent::__construct();
        $this->template_dir = ROOT . "/apps/$theme/$app/templates/$app/";
        $this->config_dir   = ROOT . "/apps/$theme/$app/configs/";
        $this->cache_dir    = ROOT . "/apps/$theme/$app/cache/";

        $this->assign(array(
            'app_name' => 'signup',
            'xhr_url' => "$site_url/aj/$app"
        ));
    }
}