Validator says style sheet doesn't exist

I received a Parse Error on Line: 15 of http://www.stephenfox.us/wp/index.php but the stylesheet does exist where the validator says it isn't. The header contains the following:

<style type="text/css" media="screen">
@import url( <?php bloginfo('stylesheet_url'); ?> );
</style>

The stylesheet does exist and it does control the output of the blog. What can I do to make the site validate? It does validate as XHTML.

Thanks,
Stephen T. Fox