System.Web.UI.ScriptManager' does not have a public property named 'Button'

i try to show ssrsc reports in asp.net web page and for this i search tutorials and i find tutorials which shows me add script manager ,reportviewer and a button when i add these 3 things in my project in .aspx page and then when i debug my project then it shows me error and here i clear that i can not add ajax tool kit reigster assembly in .aspx page for this how i add register assebly for ajax code
<%@ Register assembly="Microsoft.ReportViewer.WebForms, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" namespace="Microsoft.Reporting.WebForms" tagprefix="rsweb" %> <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server"> <div align ="center" class="adminform"> <br /><br /> <center> <div class="vpb_main_wrapper" align="center" style="lef ...