Not sure if this will help, but every time I've gotten this message, it was because the runat="server" attribute was not set in one of the skin's controls. I had to physically open the ascx file in the portal's skin folder and put that code in where it was missing, and it was always in relation to the control's id not being forced to run at the server end (which makes DNN do it's stuff). Hope that at least points you in the right direction...