AdRotator Question...

Question

I have the following code in a testpage.aspx file:

<asp:Timer ID="Timer1" runat="server" Interval="10000"></asp:Timer>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />
    </Triggers>
    <ContentTemplate>
        <asp:AdRotator ID="AdRotator1" runat="server" AdvertisementFile="~/xml/mcbAds.xml" />
    </ContentTemplate>
</asp:UpdatePanel>

I have also changed the code to put the timer in the content template.

In both case the code executes perfectly... HOWEVER, I am using master pages and when I move the code to either the master page or the content page I receieve the following error:

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.

Details: Error parsing near '<a id="ctl00_cphCont'.

QUESTION: Why do I get this error? I thik it has to do with the id of a control because, if I am not mistaken, Master/Content pages seem to modify the id's.

Any help would be greatly appreciated... I have googled this to death and spent many, many hours trying to figure out how to fix it.