Installation problems

Maybe it's a simple problem, maybe I'm too much stupid to properly run phpAlbum, but when I'm trying to access the setup page after upload via FTP, it comes with this error message:

Fatal error: require() [function.require]: Failed opening required 'setup_user.inc' (include_path='.:/usr/share/php') in /*SERVERSTRING*/gallery/setup.php on line 321

EDIT: The second time I'm trying accessing it, there's the same message plus this:

"Error creating user"

is there a way to pass this error?

thanks! :)