I was able to install horde 5 groupware on CentOS 6 successfully along with CWP.
This is what I did
1. MariaDB [(none)]> create database horde;
2. mkdir /usr/local/apache/htdocs/horde
3. pear channel-discover pear.horde.org
4. pear install horde/horde_role
5. pear run-scripts horde/horde_role
6. pear install -a -B horde/webmail
7. webmail-install [[follow the on screen instructions]]
8. edit domain-redirects.conf and add horde folder Alias
9. create /usr/local/apache/htdocs/horde/registry.d/registry.local.php
<?php
$this->applications['horde']['webroot'] = '/horde';
$this->applications['mail']['webroot'] = '/horde';
10. chown -R nobody:nobody /usr/local/apache/htdocs/horde
11. service httpd restart
12. Enjoy
http://domain-name/horde/