mikeotgaar on "[Plugin: WordPress SEO by Yoast] Google WMT rejects sitemap_index.xml"

Some possible solutions to 2nd language problem

http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-www-error-805303f4

There's also an .htaccess fix that MAY work IF you have an .htaccess security file in the wp-content folder by changing Deny from all rule to:

Order Allow,Deny
Deny from all

<Files "xml-sitemap-xsl.php">
Allow from all
</Files>