Hello,
To run ViArt shop you need to install Zend Optimizer( please ask your hosting provider to install it for you on the server).
Here you can find instructions how to install it :
http://www.viart.com/zend_optimizer_for_ecommerce_system.html
In case after installation you will still encounter problems that you have listed here, please send your
site URL and FTP details to our Support Center(support@viart.com) and our programmers will check what causes that problems.
With regards,
ViArt Support Team