I can't see mcrypt in phpinfo() in section "Additional .ini files parsed". 'php_mcrypt' have been installed. I use CentOs with nginx with PHP 5.3.3.
In /etc/php.d/mcrypt.ini I wrote extension=mcrypt.so.
I tried to change the extension path in php.ini (ex extension=/usr/lib64/php/modules/mcrypt.so), but it still doesn't work.