[horde] converting to VirtualHost problems

[Mike]

I changed my apache setup and can reach the login page using the
address http://webmail.$DOMAIN.com:8088. I enter my login and
password. The log (/tmp/horde.log) shows that I am successfully
logged in. I am sent to the address http://webmail.$DOMAIN.com:8088/index.php,
but the page shows the login page instead of the main horde
page. What setting am I missing. I expect the setting is in
$HOST:/usr/share/horde/config/conf.php.

I'm on Fedora Core 5 with the latest patches, apache, and horde.
Loggin in was working before I changed to VirtualHost and
http://webmail.$DOMAIN.com instead of http://$HOST.$DOMAIN.com/horde.

Mike