ImportError：在安装了django-cms的Django上运行时，没有名为cms的模块

我有一个基于django-cms的本地django项目。现在，突然，当我启动的virtualenv其不再工作source env/bin/activate和RUNSERVERpython manage.py runserver我得到ImportError: No module named cms。这里完整的错误信息：

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/core/management/__init__.py", line 354, in execute
    django.setup()
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/__init__.py", line 21, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/apps/config.py", line 87, in create
    module = import_module(entry)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named cms

我不明白这一点，因为一切都正常，我两周前所做的唯一事情就是将项目所在的目录从我的桌面移到另一个位置。任何人都知道如何解决此问题或原因。

点列表：

argparse (1.3.0)
binaryornot (0.3.0)
cookiecutter (0.8.0)
coverage (3.7.1)
distribute (0.7.3)
dj-database-url (0.3.0)
Django (1.7.1)
django-allauth (0.18.0)
django-appconf (0.6)
django-autoslug (1.7.2)
django-avatar (2.0)
django-braces (1.4.0)
django-cache-url (0.8.0)
django-classy-tags (0.4)
django-configurations (0.8)
django-crispy-forms (1.4.0)
django-debug-toolbar (1.2.2)
django-extensions (1.4.9)
django-floppyforms (1.3.0)
django-front (0.4.3)
django-inplaceedit (1.3.0)
django-model-utils (2.2)
django-mptt (0.6.0)
django-reversion (1.8.0)
django-secure (1.0.1)
django-sekizai (0.7)
django-wymeditor (1.0)
djangocms-admin-style (0.2.0)
djangocms-installer (0.7.2)
djangocms-text-ckeditor (2.0.5)
docutils (0.12)
html5lib (1.0b1)
Jinja2 (2.7.3)
MarkupSafe (0.23)
mock (1.0.1)
MySQL-python (1.2.5)
oauthlib (0.7.2)
Pillow (2.6.1)
pip (1.5.6)
psycopg2 (2.5.4)
Pygments (2.0.1)
python-openid (2.2.5)
pytz (2013.8)
PyYAML (3.11)
requests (2.5.1)
requests-oauthlib (0.4.2)
setuptools (8.0)
six (1.4.1)
South (0.8.4)
Sphinx (1.2.3)
sqlparse (0.1.14)
unicode-slugify (0.1.1)
virtualenv (12.0.5)
waitress (0.8.9)
Werkzeug (0.9.6)
whitenoise (1.0.6)
wsgiref (0.1.2)