Any way to run a daily script without cron jobs?

I am using PhotoQ, and my host doesn’t support cron jobs. There is a small script that calls a php file once the designated time since last post has been reached. After that time elapses, the next time the site is visited the php file is called and a post occurs. This is now broken in 2.7. Does anyone know of a simple way to fix it? Below is the contents of my index.php file:

<?php
define(‘WP_USE_THEMES’, true);
require(‘./wp-blog-header.php’);
ob_start();
require(‘./wimpq-cronpost.php’);
ob_end_clean();
?>