[horde] Reminders.php not sending reminders

[Steve Devine]

We are running horde-webmail-1.1.3 and the only way reminders get 
emailed is if a user logs into the service and uses the calendar.
I have a crontab set to run /usr/bin/php kronolith/reminders.php every 5 
mins.  I have entries in place for these in kronolith/config/conf.php:
$conf['reminder']['server_name'] = '';
$conf['reminder']['from_addr'] = '';

are there any other configs that need to be in place?
/sd
Steve Devine