I've never used cron, but here's some snippets from the cron_exec.php that ships with evo :

/**
 * Execute cron jobs.
 *
 * Example to use CLI:
 * >c:\php4\php cron_exec.php
 * >c:\php4\php-cli cron_exec.php
 */

.....


		<h1>Cron exec</h1>
		<p>This script will execute the next task in the cron queue.
		You should normally call it with the CLI (command line interface) version of PHP
		and automate that call through a cron.</p>

If you can make that all work, then hit admin > scheduler : add job, and pick prune stats as the job

¥