Looking at the sitemap there are some pages that seem to have URL's in the tags. This created an invalid page for GWT.
One being
<url>
<loc>tags/http://www.idcreative.biz.html</loc>
<lastmod>2009-11-24T13:02:59+00:00</lastmod>
<changefreq>daily</changefreq>
<priority>0.6996</priority>
</url>...
