[horde] UNable to visit critical pages from within the GUI / Admin Horde 5 groupware webmail edition latest stable

[info at interpost.biz]

I can login OK, but for critical pages like displaying the horde  
config or the imp config, I cannot get those pages to resolve. I  
receive an error_empty_response in chrome and in firefox:

La connexion avec le serveur a été réinitialisée pendant le chargement  
de la page. (the connection with the server was reset while the page  
was being loaded) errors.

I am using apache 2.4 latest stable and PHP 5.6.14 - will upgrade to  
5.6.15 as soon as debian puts it in their repositories. There must be  
some error in the horde.conf file in  
/etc/apache2/conf-available/horde.conf:

Alias /Microsoft-Server-ActiveSync /var/www/horde/rpc.php
Alias /horde /var/www/horde
<Directory /var/www/horde>
            Options Indexes Includes FollowSymLinks
            AllowOverride None
            Require all granted
            AddType application/x-httpd-php .php
           php_value include_path ".:/usr/share/php"
           php_value open_basedir "none"
          php_value upload_tmp_dir "/var/www/horde/phptmp/"
</Directory>

Is this sufficient? I don't even think the last 3 lines take effect in  
php 5.6.14 - I get the same result with or without them.

Everything looks ok in test.php, and the php.ini file being loaded is  
: 	/etc/php5/apache2/php.ini
other than that, I see in the php.ini file that
;enable_post-data-reading = Off is commented out
and
;always_populate_raw_post_data = -1 is commented out.

I don't believe either need to be used to get this working properly.

Does anyone see what is wrong here? Where to look, Default apache2 000  
and ssl conf files? Would they possibly be causing this?

Thanks for help.

Ed