[Plugin: Google XML Sitemaps] Not able to see the Sitemap file

Hi,

I recently added the Google Sitemap plugin. When I go to the settings, XML Site Map, under the status.. I get a message that There was a problem writing your sitemap file. Make sure the file exists and is writable.

I already created an empty file with the name sitemap.xml in the public_html directory in my app. server.

Can anybody guide me how to proceed on this?

Regards,
Arun