This is the error in the log-file:
aug 5 05:37:35 server-one httpd:
PHP Warning: write(): Failed opening 'Crypt/HCEMD5.php' for inclusion (include_path='.:/usr/share/pear') in /home/httpd/html/horde/lib/Secret.php on line 39
aug 5 05:37:35 server-one httpd:
PHP Fatal error: Cannot instantiate non-existent class: crypt_hcemd5 in /home/httpd/html/horde/lib/Secret.php on line 41
Does it ring a bell ?