Django 配置不当：模块django.contrib.auth.middleware

我正在运行一个Virtualenv来try 学习Django，但是无论出于什么原因，在安装Django之后，当我try 访问默认的Django开始页时，我在浏览器中得到以下错误:

出现服务器错误.请与管理员联系.

在我运行的终端窗口中，服务器显示以下错误:

错误配置:模块"django.contri.auth.midleware"没有定义"SessionAuthenticationMiddleware"属性/类

如果任何人对我为什么在viralenv中得到这个错误有任何见解，我将不胜感激.不过，我可以让服务器在非Virtualenv设置中正常运行.

下面是完整的堆栈跟踪:

Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/core/handlers/wsgi.py", line 187, in __call__
    self.load_middleware()
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/core/handlers/base.py", line 45, in load_middleware
    mw_class = import_by_path(middleware_path)
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/utils/module_loading.py", line 31, in import_by_path
    error_prefix, module_path, class_name))
错误配置:模块"django.contri.auth.midleware"没有定义"SessionAuthenticationMiddleware"属性/类
[16/Sep/2014 22:44:30] "GET / HTTP/1.1" 500 59
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/core/handlers/wsgi.py", line 187, in __call__
    self.load_middleware()
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/core/handlers/base.py", line 45, in load_middleware
    mw_class = import_by_path(middleware_path)
  File "/Users/jruecke/Python/JSON/lib/python2.7/site-packages/Django-1.6.5-py2.7.egg/django/utils/module_loading.py", line 31, in import_by_path
    error_prefix, module_path, class_name))
错误配置:模块"django.contri.auth.midleware"没有定义"SessionAuthenticationMiddleware"属性/类