Plenty of script-driven apps, particularly paid cms, encode their files so as to make sure that they will not be reverse engineered or tampered with. The majority of them use an application named ionCube PHP Encoder to do this, so if you buy a paid script and you'd like to set it up in a website hosting account, a software instrument known as ionCube Loader must be present on your server. Without this, you can't install the script or if you somehow manage to do this, it will not function properly because most of the script code will be encrypted to a point where it can't be interpreted. In this light, you need to ensure that ionCube Loader is present when you get a new website hosting account and you would like to use some paid web application. If you buy a shared hosting account and the tool is not present, it cannot be added as the entire server PHP environment shall have to be compiled again.