title: What is the meaning of the traceback?
body: <p>I am using  django-email-change-0.2.1 just to change an emailadress in the auth_user-table. When I am going to add the app emailchange in the settings.py. I get an error message!</p>
  
  <p>Actually you can install the app. But I didn't do that in the site-packages of python. I have copied the code into my code of the website.</p>
  
  <p>Root of my Website:
  /trunk/website/</p>
  
  <p>In the following path I have installed different apps.
  Path:  </p>
  
  <pre><code>/trunk/website/auth/user/emailchange  
  /trunk/website/auth/user/registraiton  
  /trunk/website/auth/user/profile
  </code></pre>
  
  <p>The last two apps are working fine. I just want to add the last app for my registration. To change the email address of an user with the app  "emailchange", so I am going to send a a verifaction link when the user is changeing his emailadress.  </p>
  
  <p>In my settings.py to run/install the app (model) I added:</p>
  
  <pre><code>Insalled_apps= {
  'auth.user.emailchange'
  }
  </code></pre>
  
  <p>But I am getting this errormessage when I add the app and call any site of my website!</p>
  
  <pre><code>Traceback:
  File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/base.py" in get_response
    91.                         request.path_info)
  File "/usr/local/lib/python2.6/dist-packages/django/core/urlresolvers.py" in resolve
    215.             for pattern in self.url_patterns:
  File "/usr/local/lib/python2.6/dist-packages/django/core/urlresolvers.py" in _get_url_patterns
    244.         patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/usr/local/lib/python2.6/dist-packages/django/core/urlresolvers.py" in _get_urlconf_module
    239.             self._urlconf_module = import_module(self.urlconf_name)
  File "/usr/local/lib/python2.6/dist-packages/django/utils/importlib.py" in import_module
    35.     __import__(name)
  File "/workspace/website/trunk/website/urls.py" in &lt;module&gt;
    5. admin.autodiscover()
  File "/usr/local/lib/python2.6/dist-packages/django/contrib/admin/__init__.py" in autodiscover
    24.             import_module('%s.admin' % app)
  File "/usr/local/lib/python2.6/dist-packages/django/utils/importlib.py" in import_module
    35.     __import__(name)
  File "/trunk/website/auth/user/emailchange/admin.py" in &lt;module&gt;
    33. admin.site.register(cache.get_model('email_change', 'EmailChangeRequest'), EmailChangeRequestAdmin)
  File "/usr/local/lib/python2.6/dist-packages/django/contrib/admin/sites.py" in register
    76.         for model in model_or_iterable:
  
  Exception Type: TypeError at /start/
  Exception Value: 'NoneType' object is not iterable
  </code></pre>
  
  <p>Any ideas? Why do I have this message?</p>