Plenty of script-driven applications, particularly paid content management systems, encrypt their files so as to make sure that they won't be reverse engineered or tampered with. Many of them use an app called ionCube PHP Encoder to do that, so, in case you get a paid script and you would like to set it up in a web hosting account, a tool known as ionCube Loader needs to be present on the server. Without this, you won't be able to install the script or if you somehow find a way to do that, it won't function effectively as most of the script code will be encrypted to a point where it can't be interpreted. In this light, you should ensure that ionCube Loader is set up if you get a new web hosting account and you'd like to use some paid web application. If you obtain a shared website hosting account and the instrument is not present, it can't be added as the whole server PHP environment will have to be compiled again.