Wordpress Sitemap Problems

When i go to the sitemap page on my website http://www.kingcountydogbiteattorney.com it shows an error. I used a plugin and it is activated and everything. Why is that?

Add the www to the url.

Have you uploaded the XSL file? (Alternatively remove the XSL styles file since XML sitemaps are really only for search engines. You could create a HTML sitemap for your human visitors.)