I don't know if this is a extension or a google problem.
This is the issue.
I have multiple wordpress sites on one domain.
I have a wordpress site on http://www.mydomain.com and a wordpress site on blabla.mydomain.com
The sitemap xml output for blabla.mydomain.com looks good but google cannot find my urls because google thinks the links are like this.
http://blabla.mydomain.com/index.php/www.mydomain.com
So google puts the main domain (www.mydomain.com) behind each url.
Anyone ?
http://wordpress.org/extend/plugins/google-sitemap-generator/