See also thread “Joomla 1.5.18 is available today, but not in Script Installers”
I also tried Add Scripts: adding the official Joomla.org download file as an installer via http, and as local file. In both cases, I got an invalid filename error.
It sure would be great if that screen gave some clues about what the correct filename would be, or if it’s trying to tell me that there’s a permissions issue in writing the file, or something that I can fix.
I’ve had some permisions issues since switching from FCGI to mod_php, not sure if that’s related.
Meanwhile, I am missing a “critical security fix” on dozens of Joomla sites, so any assistance is appreciated.