Let's see if I can help you out...
Alternative 1 - You might be missing your conf files
Try
http://your-server-ip-adress/horde/test.phpSolution - Generate new conf files
/sbin/e-smith/expand-template /home/httpd/html/horde/config/horde.conf
/sbin/e-smith/expand-template /home/httpd/html/horde/config/mime_drivers.php
/sbin/e-smith/expand-template /home/httpd/html/horde/config/registry.php
If you are missing other CONF files for IMP,TURBA etc use the same procedure... (I think you get the picture)
Alternative 2 Your CONF files are NOT correct
Following files are used to configure for webmail and other installed contribs
# /home/httpd/html/horde/config/horde.php:
$conf['prefs']['params']['password'] = '******';
# /home/httpd/html/horde/kronolith/config/conf.php:
$conf['calendar']['params']['password'] = '******';
#/home/httpd/html/horde/mnemo/config/conf.php:
$conf['storage']['params']['password'] = '******';
#/home/httpd/html/horde/nag/config/conf.php:
$conf['storage']['params']['password'] = '******';
#/home/httpd/html/horde/turba/config/sources.php:
'password' => '******',
So, good luck. I hope it helps.
Best rgds, Ergin