Google Webmaster central reports Content Analysis error [#215817]

I don't know why, but Google Webmaster central is reporting an error in my verification URL.
I certainly don't link to it nor provide it in the sitemap (it's produced by this module, but I checked it anyway)..

The error is a 'Missing title tag' and is reported to me in the Webmaster's "Dashboard > Diagnostics > Content analysis" page.

The following code fixes the problem:

--- xmlsitemap_engines.module.orig      2008-01-30 13:27:53.000000000 +0100
+++ xmlsitemap_engines.module   2008-01-30 13:36:45.000000000 +0100
@@ -261,7 +261,7 @@
 function _xmlsitemap_engines_verify($engine) {
   switch ($engine) {
     case 'google':
-      print 'Hello, Google!';
+      print '<html><head><title>Hello, Google!</title></head><body>Hello, Google!</body></html>';
       break;
     case 'yahoo':
       print variable_get('xmlsitemap_engines_yahoo_verify_string', '');