Problem with Google xml sitemap – help PLEASE!

I have installed google xml sitemap into wordpress but I have a massive problem.

The sitemap works perfectly here http:// lcd-enclosure . us / sitemap.xml but when I submit it google webmaster tools I get errors stating the following error:

“Paths don’t match
We’ve detected that you submitted your Sitemap using a URL path that doesn’t include the www prefix (for instance, http://example.com/sitemap.xml). However, the URLs listed inside your Sitemap do use the www prefix (for instance, http://www.example.com/myfile.htm).”

How can I resolve this – Please 🙁