multiple Pivot Tables, reset httpcontext(Request) in ASP.NET

Hi, I have yet posted a thread about my problem with multiple Pivot
Tables in a aspx page.

Now I have done many tests and I discovered that are the httpcontext
which is set at nothing, my tests are (the page is included in an
asp.net application):
A ASP page with 2 PT and a response.write with
Request.ServerVariables("REMOTE_USER") ever return a user correctly,
the same page, but with ASPX extension, at the first load read the
ServerVariable (created by the Application) instead the second load
don't write the ServerVariable and then the Application lose the
authentication.

Help please.

Ciao, Andrea.