1. Edit the icon for the installer script so it is "Installer", and not "C:Installer" or "Sys:System/Installer" etc - that's why it can't find it. Your other option there is to simply copy it from Sys:Utilities/Installer, to C: and any other common location.
2. All *five* zip files on aminet are windows/linux, and not one has anything to do with installer... Methinks one senses a newbie...
Robin