Problem with a custom email form I’m adding to a custom template page

I’m having an issue with a custom script that I’m adding to a custom template page. The page is https://www.lolattack.com/14/ and the issue happens when the form is submitted.

If installed properly, it should update through ajax with a message saying it has been sent. It is neither sending the e-mail nor posting the message.

Instead, it re-directs to a 404 page (https://www.lolattack.com/14/send.php?first_name=&last_name=&e_mail=&regarding=-&message=&submit=Send+Message)

I’m not sure why it’s doing it like this. It works fine if I upload it separately to my site in a different directory.

For instance: https://lolattack.com/contactform/