Sitemap Error: the incorrect namespace

Topics: ASP.NET 2.0, Business Logic Layer, Controls, Themes
Feb 24 at 9:08 AM
I replaced in my SiteMap.cs
with this
Today Google Webmaster tools give me an error in Sitemap

"The incorrect namespace
Your Sitemap or Sitemap index file namespace is not indicated correctly.
Your Sitemap or Sitemap index file does not properly declare the namespace. Expected: Detected:"

I checked my sitemap but is normal and correct (
What can be?
Can you help me?
Feb 25 at 8:40 AM