url tag: "'str' object has no attribute 'regex'"

[refreegrata]

Hello list

I know, this question has been posted and resolved before, but the solutions don't work in my situation. I don't know why.

When I try to use the "url" tag in any template an exception is raised:

"'str' object has no attribute 'regex'"

for example, with this I got the error:

------------------------------------

urls.py (main)

-------------------------------------

from django.conf.urls import patterns, include, url

urlpatterns= patterns('',

    (r'^registration/', include('apps.registration.urls')),

    (r'', 'django.contrib.auth.views.login'),

)

-------------------------------------

urls.py (registration)

-----------------------------------------

from django.conf.urls import patterns, include, url

urlpatterns= patterns('',

    (r'^login/$', 'django.contrib.auth.views.login'),

)

-----------------------------------------

login.html (in templates/registration)

-------------------------------------------------------------

{{ form }}

{% url "django.contrib.auth.views.login" %} <---here is the problem. It's just an stupid test for the problem

-------------------------------------------------------------

Fail with:

 - {% url django.contrib.auth.views.login %}

 - {% url 'django.contrib.auth.views.login' %}

 - {% url "django.contrib.auth.views.login" %}

I add this at the end of the file "settings.py":

----------------------------------------------------------

import django.template

django.template.add_to_builtins('django.templatetags.future')

----------------------------------------------------------

Including or excluding the last lines doesn't matter. The problem appear in the both cases.

I'm using Django 1.4, and Python 2.6 over Centos 6.2. Maybe I must to include something else in the settings?

Thanks for read and sorry for my bad english.