PHP Mcrypt Support
PHP‘s mcrypt support is not available. mcrypt is required for generating activate code or validate it.
安装php5-mcrypt libmcrypt4 libmcrypt-dev
sudo ln -s /etc/php5/conf.d/mcrypt.ini /etc/php5/mods-available
sudo service apache2 restart
原文：http://www.cnblogs.com/wowchky/p/5021626.html