I read a number of the posts, but was not able to solve my problem.  I
have a number of MobilePages.  Basically each pages consists of a
Lists.  The users selects a item, a postback occurs and the user is
redirected to another page, using --
RedirectToMobilePage("Page_m.aspx", false);

It works fine until the user clicks on the back button.  The previous
page displays correctly, but the postback nolonger works.  When you
select an item, you get the error

Exception: The page requires session state that is no longer available.
Either the session has expired, the client did not send a valid session
cookie, or the session state history size is too small. Try increasing
the history size or session expiry limit.]
  System.Web.UI.MobileControls.MobilePage.OnViewStateExpire(EventArgs
e) +45

System.Web.UI.MobileControls.MobilePage.LoadPageStateFromPersistenceMedium()
+313
  System.Web.UI.Page.LoadPageViewState() +18
  System.Web.UI.Page.ProcessRequestMain() +447

Web.Config

   <sessionState
           mode="InProc"
           stateConnectionString="tcpip=127.0.0.1:42424"
           sqlConnectionString="data
source=127.0.0.1;Trusted_Connection=yes"
           cookieless="false"
           timeout="20"
   />

   <!--  GLOBALIZATION
         This section sets the globalization settings of the
application.
   -->
   <globalization
           requestEncoding="utf-8"
           responseEncoding="utf-8"
  />
      <mobileControls
cookielessDataDictionaryType="System.Web.Mobile.CookielessData" />

This happens on IE and Firefox.  This does not happen on AudioVox PIE.

Thanks,

Roger