I have an ASP.NET site that uses JQuery and ASP.NET UpdatePanel and ScriptManager. On one page in particular, I get a javascript error:

sys.webforms.pagerequestmanagerservererrorexception: Index and length must refer to a  location within the string.  Parameter name:length

ScriptResourse.axd Code: 0

Here's what's in the master page:

<asp:ScriptManager runat="server" ID="ScriptMgr"></asp:ScriptManager>

<asp:UpdatePanel runat="server" ID="UpdatePanelMaster">
    <ContentTemplate>

    </ContentTemplate>
</asp:UpdatePanel>

In the page in question:

<asp:Content ID="ContentHeadEdit" ContentPlaceHolderID="ContentHeadMaster" Runat="Server">

    <script type="text/javascript">
    $(document).ready(function() {
        $('#<%= ButtonSave.ClientID %>').button();

        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);

        function EndRequestHandler(sender, args) {
            $('#<%= ButtonSave.ClientID %>').button();
        }
    });
    </script>

</asp:Content>