output cache problem : when any user control registered on a page page not cached

[SharpSmith]

hi all
i have a strange problem with caching

very simple cache test page with fallowing code is not cached at
all(browser/server whatever):
<%@ Register TagPrefix="uc1" TagName="NewHomePageModule"
Src="~/Home/Module/NewHomePageModule.ascx" %>
<%@ Page language="c#" %>
<%@ OutputCache Duration="60" VaryByParam="*" %>
<h1>test form</h1>
<h2><%=DateTime.Now%></h2>

but when you remove this line :
<%@ Register TagPrefix="uc1" TagName="NewHomePageModule"
Src="~/Home/Module/NewHomePageModule.ascx" %>

and i stay with :

<%@ Page language="c#" %>
<%@ OutputCache Duration="60" VaryByParam="*" %>
<h1>test form</h1>
<h2><%=DateTime.Now%></h2>

the caching starting to work correctly

the stranger thing is that happening only on production box
(IIS6/ASP.Net 1.1) and on dev box (IIS5/ASP.NET 1.1) code work properly
in both cases

i gave here example as simple as posssible, actually the whole caching
framework we developed is not working on production machine

please help anybody has an idea or direction to trouble-shoot this
Thanks much anyway for your attention
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From: Yevgeniy Kuznetsov