Urban Giraffe Support

I just installed Sniplets. All I want to do (initially) is to run some PHP code within one of my pages (Sign Up page).

I uploaded and activated Sniplets.

I enabled PHP code to run.

I created a 'local' Sniplet named:
php_include_signup_form

which has the value of:
<?php include "../includes/signup_form.php";?>

I put the Sniplet code into the html of my web page by clicking the Sniplet button, then replacing the 'Sniplet name' with my Sniplet name:
[php_include_signup_form]

What I see on my web page:
[php_include_signup_form]

Here is the web page:
http://www.kempstuff.com/blog/?page_id=33

The code isn't running, it just shows up on my web page.

Please help.