Colin,
I found a cure to the cron problem

i needed to add
PHP Code:
include_once './includes/cron/vbemailreply.php';
in my index.php above
PHP Code:
eval('$navbar = "' . fetch_template('navbar') . '";');
I believe it add a query to yuo home page doing this but it works for me.
Also on a different note you might want to add a notice on the first post stating that PHP compiled with IMAP is a requirement.