I have a HTML file and a PHP file in the same folder on the remote server. From the URL, I call the HTML file and the HTML file calls the PHP file when form is submitted.

But it is not going correctly. When I submit the Form, it dislays error:

500 - Internal server error. There is a problem with the resource you are looking for, and it cannot be displayed.

What is the reason?

Edited:

The source of the PHP file is available [here][1].

The Form tag in the HTML file looks like:

[1]: http://stackoverflow.com/questions/2470088/code-to-send-email-not-workingstrong text