Microsoft.Office.Interop.Excel.Worksheet does not contain a definition for InsertRow

I want to dynamically insert few rows in an excel sheet , but when i tried to use the below code as suggested over one of the forums but its throwing an error.

//Inserting 10 rows into the worksheet starting from 3rd row

 worksheet.Cells.InsertRows(2,10);

Microsoft.Office.Interop.Excel.Worksheet doesnot contain a definition for 'InsertRow'
and no extension method 'InsertRow' acceping a 1st argument of type 'Microsoft.Office.Interop.Excel.Worksheet' 

can any one help me in this...