File includes

I have a word press page, that contains some PHP code, designed to push a FORM to the page. Once I fill the form, and hit submit, I would like another PHP script to be called.

The problem I am having, is that I do not want to have that second script in the main WordPress directory, and instead I want it in my own general include directory, /home/acme/include. The WordPress install directory is /home/acme/public_html

I tried hardcoding the path, but when I submit the form, WordPress pads on http://wwww.acme.com/home/acme/include/filename.php

Is there any way to get round this?