SharePoint 2010 Search: Internal server error exception: System.NullReferenceException

When we try to perform search on http://sharepoint10/_layouts/OSSSearchResults.aspx we get following error Internal Server Exception Correlation ID : 7b8967ae-1ff7-41bc-8ea4-5153ef9d1a6c ULS Logs: 0x3DDC SharePoint Server Search Query fm9a Unexpected CoreResultsWebPart::OnInit: Exception initializing: System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.Office.Server.Search.WebControls.CoreResultsWebPart.SetPropertiesOnQueryReader() at Microsoft.Office.Server.Search.WebControls.CoreResultsWebPart.OnInit(EventArgs e) 7b8967ae-1ff7-41bc-8ea4-5153ef9d1a6c 03/09/2011 10:13:23.93 w3wp.exe (0x3BE0) 0x3DDC SharePoint Server…

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