Erro trying to use RadDataForm, does not exist

[Ying]

I tried to use the RadDataForm, but get
The type 'telerik:RadDataForm' was not found. Verify that you are not missing an assembly reference and that all referenced assemblies have been built. 
I am using build 2011_3_1220 release

here is my xaml code:
<telerik:RadWindow x:Class="GISWeb.UserControls.window_bcaa"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
      xmlns:data="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Data"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <Grid x:Name="LayoutRoot" Background="White">
        <telerik:RadDataForm ></telerik:RadDataForm>
    </Grid>
</telerik:RadWindow>

[Maya]

Hello Ying,

You need to make sure you have Telerik.Windows.Controls.Data assembly referenced in your application. Can you please verify it and let me know in case you are still unable to work with RadDataForm control ? 

All the best,
Maya
the Telerik team