I got this error while testing a sample provided by Raj Kaimal http://weblogs.asp.net/rajbk/archive/2010/05/09/creating-an-asp-net-report-using-visual-studio-2010-part-1.aspx
I alraedy tried the solution from this forum to make the folder as an application in IIS. There are actually more than one issue I am facing:
1. Compile no error
2. In Design window of Index.aspx, it says: failed to create designer 'Microsoft.Reporting.Webforms.ReportViewer, Microsoft.ReportViewer.WebForms, Version =10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
3. I run the site and try to open index.aspx, it shows: 
Server Error in '/NorthWindReports' Application. Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser Error Message: Unrecog ...

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