Vision Helpdesk setup files are encoded with Zend Guard and in order to run it you must have decryption tool i,e Zend Guard Loader.
Zend Guard Loader is a FREE PHP extension that runs PHP scripts encoded by Zend Guard. The Zend Guard Loader translates encoded files to a format that can be parsed by the Zend Engine.
Below are steps for installing Zend Guard Loader
1) Download Zend Guard Loader according to your server PHP version and operating system.
2) Extract the ZendGuardLoader.so (Linux) or ZendLoader.dll (Windows) that corresponds to your PHP version.
In your server php.ini file search for extension_dir - it defines the path where you have to upload your ZendGuardLoader.so or dll file.
<?php echo phpinfo(); ?>
5) On your info.php page if you see Zend Guard Loader that means you have installed it correct.