Lots of script-driven applications, especially paid content management systems, encode their files to ensure that they will not be reverse engineered or tampered with. Most of them use an app known as ionCube PHP Encoder to do that, so, in case you obtain a paid script and you would like to install it in a website hosting account, a software instrument known as ionCube Loader needs to be present on your server. Without it, you will not be able to install the script or if you somehow manage to do that, it will not work efficiently as most of the script code will be encoded to a point where it cannot be interpreted. That's why, you should ensure that ionCube Loader is present when you get a new hosting account and you wish to employ some paid web app. If you acquire a shared hosting account and the tool is not present, it can't be added since the entire server PHP environment will have to be compiled again.