ScriptManager is required on the page to use ASP.NET AJAX Script Components

Hi there

We made some significant changes to 1.4 and decided to upgrade to 1.5.  We have spent more than a day with Winmerge just to get the changes merged with the new solution.  After 1 day of merging and another debugging just to get the solutin to compile I now get the following error when trying to view a product details page:
[InvalidOperationException: A ScriptManager is required on the page to use ASP.NET AJAX Script Components.]
   AjaxControlToolkit.ScriptObjectBuilder.RegisterCssReferences(Control control) +1014
   AjaxControlToolkit.ScriptControlBase.OnLoad(EventArgs e) +59
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627


We checked the web.config file and it shows the correct config for Ajax:
<controls>
        <add tagPrefix="ajaxToolkit" namespace="AjaxControlToolkit" assembly="AjaxControlToolkit"/>
        <add tagPrefix="HTMLEditor" namespace="AjaxControlToolkit.HTMLEditor" assembly="AjaxControlToolkit"/>
        <add tagPrefix="nopCommerce" namespace="NopSolutions.NopCommerce.Controls" assembly="Nop.Controls"/>
        <add tagPrefix="nopCommerce" namespace="NopSolutions.NopCommerce.Controls.Payment.Validators" assembly="Nop.Controls"/>
        <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        <add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      </controls>

Does anyone have any suggestions?  I am out of ideas asto what is going on here and how to fix it.

Don't worry

I compared pages again and the following on the VariantsInGrid didn't make it over during the merge:
<ajaxToolkit:ToolkitScriptManager runat="Server" EnableScriptGlobalization="true"
    EnableScriptLocalization="true" ID="sm1" ScriptMode="Release" CompositeScript-ScriptMode="Release" />
I think this will work now..