DC2NET Links

I want to add my sitemap into google webmaster. I need easy way to submit my sitemap into webmaster. i have found a proccess by searching on google. they says that your site map will be yourdomai.blogspot.com/atom.xml or rss.xml
but when i give my blogsite to webmaster as this format its gives a error msg:

“The Sitemap must be located at http://sample.blogspot.com/. To add a Sitemap at http://sample.blogspot.com/http://sample.blogspot.com/, first add that site to your account and then click the Add a Sitemap link beside it.”

what was wrong!!!
please help me.