Piping Email to PHP Script

I am setting up filters on one of my email addresses, so that when it receives an email including a specific string, the filter pipes it to the program at username/foldername/script.php. I have tried many variations to get it to the right place so it can be processed, does it have to be, including /home/username/foldername/script.php, I looked at so many different things. username is my account, foldername is permission 0700 like cpanel.net recommended, I tried with and without the hashbang #!/usr/bin/php -q so please give direction.