Some of Horde's configuration files are missing or unreadable

prefs.php

This file controls the default preferences for Horde, and also controls which preferences users can alter.

conf.php

This is the main Horde configuration file. It contains paths and basic items that apply to the core framework and all Horde applications.

mime_drivers.php

This file controls the global set of MIME drivers for the Horde framework, allowing applications to make use of programs such as enscript or mswordview to render content into HTML for viewing in a browser.

nls.php

This file provides localisation support for the Horde framework.

registry.php

The registry is how Horde applications find out how to talk to each other. You should list any installed Horde applications that you have here.

Create these files from their .dist versions in /usr/share/psa-horde/config and change them according to your needs.