add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
in web.config so that i am getting error
do i use rad script manager with out this tag in web.config

telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">

<AjaxSettings>

<telerik:AjaxSetting AjaxControlID="RadGrid1">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="grdSearch" />

</UpdatedControls>

</telerik:AjaxSetting>

</AjaxSettings>

</telerik:RadAjaxManager>

<telerik:RadGrid ID="grdSearch" AllowPaging="true" AllowSorting="true" runat="server" AutoGenerateColumns="false"

OnItemDataBound="grdSearch_ItemDataBound" OnNeedDataSource="grdSearch_NeedDataSource">

<ExportSettings>

<Pdf FontType="Subset" PaperSize= "A4" />

<Excel Format="Html" />

<Csv FileExtension="csv" ColumnDelimiter="Comma" RowDelimiter="NewLine" />

</ExportSettings>

<MasterTableView TableLayout="Auto">

<Columns>

<telerik:GridHyperLinkColumn

DataTextFormatString="'{0}'"

DataNavigateUrlFields="DebtorId"

UniqueName="DebtorsNo"

DataNavigateUrlFormatString="DebtorDetails.aspx?did={0}"

HeaderText="Debtors No"

DataTextField="DebtorsNo">

</telerik:GridHyperLinkColumn>

<telerik:GridHyperLinkColumn

DataTextFormatString="'{0}'"

DataNavigateUrlFields="DebtorId"

UniqueName="DebtorName"

DataNavigateUrlFormatString="DebtorDetails.aspx?did={0}"

HeaderText="Name"

DataTextField="DebtorName">

</telerik:GridHyperLinkColumn>

<telerik:GridBoundColumn

DataField="Postcode"

DataType="System.String"

HeaderText="Postcode"

SortExpression="Postcode"

UniqueName="Postcode">

</telerik:GridBoundColumn>

<telerik:GridTemplateColumn HeaderText="Is Active" UniqueName="TemplateColumn">

<ItemTemplate>

<asp:CheckBox id="statusChkBox" runat="server"

Checked='<%# Eval("Active") %>' Enabled="false">

</asp:CheckBox>

</ItemTemplate>

</telerik:GridTemplateColumn>

</Columns>

</MasterTableView>

<PagerStyle Mode="NextPrevAndNumeric" />

<FilterMenu EnableTheming="True">

<CollapseAnimation Duration="200" Type="OutQuint" />

</FilterMenu>

</telerik:RadGrid>

void Page_Load(object sender, EventArgs e)

{

if (!Page.IsPostBack)

{

CommonHelper.SetFocus(txtSearch);

grdSearch.DataSource =

new int[] { };

//Response.Redirect("NotImplemented.aspx");

void BindGrid()

{

DebtorCollection debtorCollection = new DebtorCollection();

try

DebtorManager.Search(txtSearch.Text);

}

catch (Exception ex)

{

lblError.Text = ex.Message;

}

grdSearch.DataSource = debtorCollection;

//grdSearch.DataBind();

protected void btnSearch_Click(object sender, EventArgs e)

{

//BindGrid();

protected void grdSearch_ItemDataBound(object sender, GridItemEventArgs e)

{

//if (e.Item is GridPagerItem)

//{

// lblTotalNoRecords.Text = "Total number of records found: " + (e.Item as GridPagerItem).Paging.DataSourceCount.ToString();

//}

protected void grdSearch_NeedDataSource(object source, Telerik.Web.UI.GridNeedDataSourceEventArgs e)

{

BindGrid();

}