You MUST add this to cron.php: define( 'CRMCRON', true );

gistfile1.php

<?php
// Add this to wp-content/mu-plugins/crm.php

if( class_exists( 'CRM_Utils_System_WordPress' ) ) {
  class Fix_CRM_Cron extends CRM_Utils_System_WordPress {
		
		function __construct() {
			if( ! defined( 'CRMCRON' ) )
				return;
			add_filter('template', array( &$this, 'change_theme') );
			add_filter('option_template', array( &$this, 'change_theme') );
			add_filter('option_stylesheet', array( &$this, 'change_theme') );
		}
		function change_theme() {
		    // Alternate theme
		    return 'twentyten';
		}	
	}
}
new Fix_CRM_Cron;