[Solved] Error using PanelBar and RenderAction

[Maria]

Hi All!!!.
I hava a problem working with PanelBar and I can't found what I'm doing wrong.
If I call an action of a controller with the following code in the view, the PanelBar works perfect. But If in the Site.Master I call a Html.RenderAction("Action", "Controller" and I create a partial view with the same code I get the following error:
"HttpException- Error executing child request for: HttpHandlerUtil ServerExecuteHttpHandlerAsyncWrapper".
Any idea about what I'm doing wrong ???.
Thanking in advance for any help ....

Maria

This is the code for the view. The only different is in the view that is working is .aspx and in the view that I get the problem is a parcial view .ascx

<%= Html.Telerik().PanelBar()
   .Name("MenuPanel")
   .HtmlAttributes(new { style = "width: 200px;" })
   .BindTo(Model, mappings =>
       {
           mappings.For<ModeloDatos.MenuPadre>(binding => binding
               .ItemDataBound((item, ParentMenu) =>
                   {
                       item.Text = ParentMenu.Texto;
                              })
                   .Children(ParentMenu => ParentMenu.MenuHijo));
           mappings.For<ModeloDatos.MenuHijo>(binding => binding
               .ItemDataBound((item, ChildMenu) =>
                   {
                       item.Text = ChildMenu.Texto;
                                              }
                   }));

           })
%>