I had submitted the google sitemap for my site a month ago to Google Webmaster site.. The urls were spidered initially. Later on 25 sep i got a status message as "Errors" in the sitemap section. Also in the diagnostic section there were no errors except for "unreachable urls" that were showing the maximum links. I got the detail as robots.txt unreachable. I have placed the robots.txt and sitemap.xml in the root folder in FTP. Can anyone give any solution for this problem