After I have upgraded my system from Ubuntu 13.04 to 13.10 several problems have occurred with apache, mysql and php configurations.
I solved most of them but I can
just found on php.net
Note, for Ubuntu, simply installing php5-mcrypt did not get mcrypt to work. You need to execute the following commands as root to enable it:
apt-get install php5-mcrypt
mv -i /etc/php5/conf.d/mcrypt.ini /etc/php5/mods-available/
php5enmod mcrypt
service apache2 restart
http://php.net/manual/en/mcrypt.installation.php#114609