My feed, http://www.yellowstonetreasures.com/feed/, is not validating at the W3C service. Now I am even getting an internal server error: The server encountered an internal error or misconfiguration and was unable to complete your request. So I am going to contact my web host, but perhaps you can help me anyway.
In reading other posts, I gather that there should be a wp-rss2.php file or something like that, but I could not find it. I looked through the .php files without editing them, as far as I know.