RadWindow is not opened when click on Grid Row

[Sachita]

    function PendingRowSelected(row) {
         var guid = $find("<%=PendingRadGrid.ClientID%>").get_masterTableView().get_selectedItems()[0].getDataKeyValue("Guid");
        var radWindow = Quest.Utilities.WindowUtil.openRADWindow("PendingEditWindow", "Portlets/ConnectData/PendingEdit.aspx?id=" +guid);                          //radWindow value as undefined
        radWindow.Restore();
        var close = document.getElementById("CloseButton" + radWindow.Id);
        close.onclick = CloseRadWindow;
    }

 

Can anyone please help to resolve?