am trying to use the AJAX PopupExtender for ASP.Net 2.0.

I am trying to extend the example downloaded from asp.net ajax
website. The example uses a Textbox as the TargetID.

I have tried changing the TargetID to a Label on my page but I receive
the following error:
Assertion Failed: No default property supported for control ... of
type ""

It fails in this JavaScript Function:
_close : function(result) {
var e = this.get_element();if (null != result) {
if ('$$CANCEL$$' != result) {
if (this._commitProperty) {
e[this._commitProperty] = result;} else if ('text' == e.type)//Fails
here {
e.value = result;} else {
Sys.Debug.assert(false,
String.format(AjaxControlToolkit.Resources.PopupControl_NoDefaultProperty,
e.id, e.type));}
if (this._commitScript) {
eval(this._commitScript);}
}

It fails here: if ('text' == e.type) it seems that e.type is
"undefined".

Any help on replacing text in a label control using the PopupExtender
would be great!

<asp:Label ID="MyLabel" runat="server" Style="left: -542px; position:
relative; top: 32px">Northing</asp:Label>
           <br />
           <asp:Panel ID="Panel1" runat="server"
CssClass="popupControl">
               <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                   <ContentTemplate>
                       <asp:RadioButtonList ID="RadioButtonList1"
runat="server"
                       AutoPostBack="true"
OnSelectedIndexChanged="RadioButtonList1_SelectedIndexChanged"
                           Width="146px">
                           <asp:ListItem Text="Scott Guthrie"></
asp:ListItem>
                           <asp:ListItem Text="Simon Muzio"></
asp:ListItem>
                           <asp:ListItem Text="Brian Goldfarb"></
asp:ListItem>
                           <asp:ListItem Text="Joe Stagner"></
asp:ListItem>
                           <asp:ListItem Text="Shawn Nandi"></
asp:ListItem>
                       </asp:RadioButtonList>
                   </ContentTemplate>
               </asp:UpdatePanel>
           </asp:Panel>
           <br />
       <cc1:PopupControlExtender ID="PopupControlExtender1"
runat="server"
       CommitScript="e.value += ' - SEND A MEETING REQUEST!';"
       PopupControlID=Panel1 Position=bottom TargetControlID=MyLabel>
       </cc1:PopupControlExtender>

protected void RadioButtonList1_SelectedIndexChanged(object sender,
EventArgs e)
   {
       if ((String.IsNullOrEmpty(RadioButtonList1.SelectedValue)) ==
false)
       {
           // Popup result is the selected task

PopupControlExtender.GetProxyForCurrentPopup(this.Page).Commit(RadioButtonList1.SelectedValue);
       }
       // Reset the selected item
       RadioButtonList1.ClearSelection();
   }