So I'm trying to get SMF up and running on my site; first, I tried using the auto-installer provided through Fantastico, which gave me 1.0.5[Patched-1]. When that didn't work I tried manually installing 1.0.7 from this website. In both cases, the moment I tried accessing any page of the forums I got the same error (meaning I could never run install.php for ym second, manual, install attempt):
Forbidden
You don't have permission to access /php.fcgi/forums/index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
I have no idea what this means, nor any idea how to fix it.
I would follow all the instructions for installing SMF and certainly the one for chmodding the files and folders to 777 while you are installing.
It is common for Fantastico to sometimes not set the correct permissions for certain folders.
Information about installing SMF manually can be found here:
http://www.simplemachines.org/community/index.php?topic=6765.0
:)