[Django] ERROR (EXTERNAL IP): Internal Server Error: /events/venues/France/97/edit/

Traceback (most recent call last):

  File "/usr/lib/pymodules/python2.6/django/core/handlers/base.py", line 111, in get_response
    response = callback(request, *callback_args, **callback_kwargs)

  File "/usr/lib/pymodules/python2.6/django/contrib/auth/decorators.py", line 33, in _wrapped_view
    from django.contrib.auth.views import redirect_to_login

  File "/usr/lib/pymodules/python2.6/django/contrib/auth/views.py", line 8, in <module>
    from django.utils.http import base36_to_int, is_safe_url

ImportError: cannot import name is_safe_url