The website for the Lunar PIXImus application doesn't provide any information, which means that you have to rely on the available documentation provided by the application. Therefore, start the software and either go to Help > Contents or access the documentation found in the installation directory.
A General Protection Fault is caused by the memory or because of compatibility/file corruption. The first thing I recommend is to reinstall the program, then if it doesn't work, go to Help > About and get in touch with the developers.