A lot of script-driven applications, especially paid content management systems, encode their files so as to make sure that they will not be reverse engineered or tampered with. Many of them use an app named ionCube PHP Encoder to do this, so if you acquire a paid script and you wish to set it up in a website hosting account, a tool known as ionCube Loader needs to be present on the server. Without this, you can't install the script or if you somehow find a way to do that, it will not function appropriately because most of the script code will be encoded to a point where it cannot be interpreted. That's why, you need to ensure that ionCube Loader is present when you get a new hosting account and you want to take advantage of some paid web application. If you purchase a shared website hosting account and the instrument is not present, it can't be added as the entire server PHP environment shall have to be compiled again.