Cannot create column with the specified type name: GridHTMLEditorColumn 

If I change the bundColumn to GridBoundColumn, then no error . Please help!!

-----------------

below is my code:

protected void Page_Load(object sender, EventArgs e)

{ 

GridHTMLEditorColumn boundColumn = new GridHTMLEditorColumn();

boundColumn.DataField =

"French";

boundColumn.HeaderText =

"French";

boundColumn.UniqueName =

"French";

this.RadGrid1.MasterTableView.Columns.Add(boundColumn);

}

protected void RadGrid1_NeedDataSource(object source, GridNeedDataSourceEventArgs e)

{

//bind grid to db
DataSet ds;
ds = SqlHelper.ExecuteDataset(ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString, "sp_Languages_Get"); 

RadGrid1.DataSource = ds;

}

<

html xmlns="http://www.w3.org/1999/xhtml">

<

head runat="server">

<title></title>

</

head>

<

body>

<form id="form1" runat="server">

<div>

<telerik:RadScriptManager ID="RadScriptManager1" Runat="server">

</telerik:RadScriptManager>

<telerik:RadGrid ID="RadGrid1" runat="server" AutoGenerateColumns="False"

GridLines="None" onneeddatasource="RadGrid1_NeedDataSource">

<

MasterTableView autogeneratecolumns="True">

<

RowIndicatorColumn>

<

HeaderStyle Width="20px"></HeaderStyle>

</

RowIndicatorColumn>

<

ExpandCollapseColumn>

<

HeaderStyle Width="20px"></HeaderStyle>

</

ExpandCollapseColumn>

<Columns>

<telerik:GridEditCommandColumn>

</telerik:GridEditCommandColumn>

<telerik:GridButtonColumn CommandName="Delete" Text="Delete"

UniqueName="column">

</telerik:GridButtonColumn>

</Columns>

</

MasterTableView>

</telerik:RadGrid>

</div>

</form>

</

body>

</

html>

Thanks