Incomprehention d'un message d'erreur

bonjour,
s'il vous plait je n'arrive à comprendre et à savoir ce qu'il faut que je fasse avec ce message d'erreur merci pour votre aide vous etes formidables
SERVER ERROR IN '/' APPLICATION
objet reference not set to an instance of an objet
description: an unhandlest occured during the execution of the current web request please review the stack trace for more information about the error and where it original in the code
source error
the source error that generated this unhandled exception can only be shown when compiled in debug mode to enable this please follow one of the below steps then request the URL
1 add a "debug=true" directive at the file that generated the error example
<%@pagelanguage="C#"debug="true"%>
or
2 add the following section to the cnfiguration file of your application
<configuration>
<system.web>
<compilation debug="true"/>
<system.web>
</configuration>
note that this second technique will cause all files whithin a given application to be compiled in debug mode The first technique will cause only that particular file to be compiled in debug mode
important running applications in debug mode does incur a memory/performance overhead you should make sure that an application has debugging disabled before deploying into production scenario
stack trace
(NullReferenceException: Object reference not set to an instance of an objet.)
M123.web.modules.compfilter..ctor
asp.contents_aspx.gzipcompressor() +136
asp.contents_aspx.page_init() +5
system .web.util.arglesseventhandlerdelagateproxy.callback(objectsender,eventargs e)
system.web.ui.control.oninit(rnentargs e) +67

un immense merci d'avance ceci apparait sur le site tchatche à la place des noms des contacts.
bonne journée et merci encore
mick