.htaccess 500 error

What is causing a 500 error with the below code in the .htaccess file?

User-a开发者_StackOverflowgent: * 
Disallow: /

RewriteEngine On

RewriteBase /
RewriteRule ^([a-zA-Z0-9\-_]+)\.shtml /$1.php
RewriteRule ^Marketing-Resources/([a-zA-Z0-9\-_]+)\.shtml /Marketing-Resources/$1.php
RewriteRule ^Affiliates/([a-zA-Z0-9\-_]+)\.shtml /Affiliates/$1.php
RewriteRule ^Help/([a-zA-Z0-9\-_]+)\.shtml /Help/$1.php
RewriteRule ^Specialty-Lists/([a-zA-Z0-9\-_]+)\.shtml /Specialty-Lists/$1.php

If it matters the file is inside the folder of a subdomain.

User-agent: * 
Disallow: /

These two lines usually belong to robots.txt, not .htaccess...