massimedia on "cannot access install.php"

Hi t-p, thanks for your suggestions.
unfortunately, i did all the above already before, no luck.
more precisely, the error is "Internal Server Error" nothing more is clarified.
i even tried to delete wp-config.php hoping to be asked to configure it once more but the error message doesn't change...
what drives me nuts is that i did the same procedure for a Windows server, same computer, same all, and it worked. cannot figure out. anything else?
thanks again