If you've only just enabled it, then there should not be anything wrong with it.
Are you trying to access it from inside or outside your local network?
Please show output of config show horde
Please remove the the dbPassword
config show imap
As you are trying to login to webmail please do
tail -f /var/log/messages
and post that output as well.
The last thing you should do is remove the horde rpms and re-install them, but if you'd rather do that then just yum remove xxx
xxx = the individual horde rpms. You should remove 8 rpms, then yum install e-smith-horde e-smith-imp e-smith-ingo e-smith-turba
That should pull in the horde dependencies, 8 total rpms to install, then signal-event post-upgrade ; signal-event reboot
John