Zend Optimizer is a must for running ViArt Shop version 3.6 amd lower. Please, contact your hosting company and enquire if they would install this for you, it is a free piece of software. ViArt currently provides its own hosted service which supports Zend if you would be interested in this: http://www.viart.com/php-web-hosting Also, we would suggest to check our 30-Day Free Trial on our server at: http://www.viart.com/hosting_trial.php Note: starting from version 4.0 Zend Optimizer is not required anymore.