Pre-init problem on web server

Hello,
 
I wrote a code file that overrides the pre-init event of all Web pages (to switch materpages). This works great in my development environment. But when I publish my pages to a web server (2008 R2) the code is not called anymore.
Please see my general code below (I did delete the actual code, since its irellevant because the procedure is not called at all)
 
Imports System.Web Imports System.Web.SessionState.HttpSessionState Imports System.Data Public Class MasterPageModule Implements IHttpModule Public Sub Dispose() Implements IHttpModule.Dispose End Sub Public Sub Init(ByVal context As System.Web.HttpApplication) Implements IHttpModule.Init AddHandler context.PreRequestHandlerExecute, AddressOf Application_PreRequestHandlerExecute End Sub Public Sub Application_PreRequestHandlerExecute(ByVal sender As Object, ByVal e As EventArgs) Dim app ...