错误django.core.exceptions.ImproperlyConfigured: 'django_mongodb_engine' isn't an available database b

Traceback (most recent call last):
  File "/Users/nohackcc/Documents/workspace/ARingServer/ARingServer/manage.py", line 10, in 
    execute_from_command_line(sys.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 429, in execute_from_command_line
    utility.execute()
  File "/Library/Python/2.7/site-packages/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Library/Python/2.7/site-packages/django/core/management/base.py", line 209, in execute
    translation.activate('en-us')
  File "/Library/Python/2.7/site-packages/django/utils/translation/__init__.py", line 100, in activate
    return _trans.activate(language)
  File "/Library/Python/2.7/site-packages/django/utils/translation/trans_real.py", line 202, in activate
    _active.value = translation(language)
  File "/Library/Python/2.7/site-packages/django/utils/translation/trans_real.py", line 185, in translation
    default_translation = _fetch(settings.LANGUAGE_CODE)
  File "/Library/Python/2.7/site-packages/django/utils/translation/trans_real.py", line 162, in _fetch
    app = import_module(appname)
  File "/Library/Python/2.7/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/Library/Python/2.7/site-packages/django/contrib/admin/__init__.py", line 3, in 
    from django.contrib.admin.helpers import ACTION_CHECKBOX_NAME
  File "/Library/Python/2.7/site-packages/django/contrib/admin/helpers.py", line 3, in 
    from django.contrib.admin.util import (flatten_fieldsets, lookup_field,
  File "/Library/Python/2.7/site-packages/django/contrib/admin/util.py", line 1, in 
    from django.db import models
  File "/Library/Python/2.7/site-packages/django/db/__init__.py", line 78, in 
    connection = connections[DEFAULT_DB_ALIAS]
  File "/Library/Python/2.7/site-packages/django/db/utils.py", line 93, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/Library/Python/2.7/site-packages/django/db/utils.py", line 51, in load_backend
    raise ImproperlyConfigured(error_msg)
django.core.exceptions.ImproperlyConfigured: 'django_mongodb_engine' isn't an available database backend. 
Try using django.db.backends.XXX, where XXX is one of:
    'dummy', 'mysql', 'oracle', 'postgresql', 'postgresql_psycopg2', 'sqlite3'
Error was: cannot import name timezone

明明配置了pythonpath，包含了django_mongo_engine,pymongo,django-toolbox,但还是有问题，尚不清楚，有人说是Django版本问题，继续查

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2014.8.6补充

问题原因是django-nonrel版本安装的为django1.3,而timezone是在django1.4以后的版本中才可以使用。

解决办法：下载1.4版本及以上的Django-nonrel版本，当前为1.5版，https://github.com/django-nonrel/django

相关Django＋mongo的安装可以参考：http://blog.csdn.net/nohackcc/article/details/38399291