HTTP 500 error

I am trying to upload files I found at http://www.html-form-guide.com/php-form/php-registration-form.html. They are unzipped and in my root directory on FTP. I can access the page http://www.satorinectar.com/source but that is all.

If I try to run php script (www.satorinectar.com/sources/register.php) it brings me to a HTTP 500 error. I edited the membership_config file to include all of my database information and uploaded it to the server. What am I missing?

I just successfully uploaded a forum so I understand the process but this doesn’t have an “install.php” to run it like the forum did. Any help is greatly appreciated!

Thanks.