In template section Fonts when select Google Font Directory get 404. That’s an error. ... Can you check this. I think this is perhaps one of the reasons why we started the site to give a hateful message 0 String could not be parsed as XML.
This problem is connected with fact that Google have changed an URL to theirs fonts directory to: http://www.google.com/fonts - we will update it in the nearest major release. But this is totally not connected with your error message - most probably it is returned by some extensions which parses external XML data.