Issue :
Horde webmail screen of a domain is displaying a blank screen.
Cause :
May be due to recent PHP upgrade. You may find the following entries in error log (/etc/httpd/logs/error_log)
================
PHP Fatal error: require_once() [function.require]: Failed opening required ‘Horde/String.php’ (include_path=’/usr/share/psa-horde:/usr/share/psa-horde/pear:.’) in /usr/share/psa-horde/lib/Horde/Browser.php on line 4
=================
Fix :
Edit /etc/httpd/conf.d/zz010_psa_httpd.conf
Replace all occurance of
php_admin_value include_path “/usr/share/psa-horde:/usr/share/psa-horde/pear:.”
to
php_admin_value include_path “/usr/share/psa-horde/lib:/usr/share/psa-horde:/usr/share/psa-horde/pear:.”
Restart Apache
Reference : http://forum.parallels.com/showthread.php?t=76327
