RSS for CMS control problem

Hi,
I have implemented Stefan's RSS component
(http://blogs.technet.com/stefan_gossner/articles/208941.aspx)
but
getting the error:
This operation requires the context of a Posting. The request must have
a valid Posting Url or QueryString so that the CmsHttpContext.Posting
will not be null.
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details:
Microsoft.ContentManagement.WebControls.WebAuthorException: This
operation requires the context of a Posting. The request must have a
valid Posting Url or QueryString so that the CmsHttpContext.Posting
will not be null.

Source Error:


Line 31: 			//
Line 32: 			InitializeComponent();
Line 33: 			base.OnInit(e);
Line 34: 		}
Line 35:

Is anyone can give me an idea what is valid posting and where should I
have it entered.
Thank you in advance!
Tatyana