Django: ‘current_tags’ is not a valid tag library

I would suggest the following:

1. (Most likely) You haven’t installed one of the dependencies of your tag library. Check the imports inside the current_tags.py module.

2. Make sure the application that includes the tag library is registered in settings.py under INSTALLED_APPS.

3. Make sure that you can successfully import the tag library.

   python manage.py shell
   >>> from app.templatetags import current_tags
   

   This boils down what the following link recommends, which is that the error itself tends to mislead you about where it’s looking for a template from. It silently ignores errors on import, which means current_tags.py itself might have a syntax error or another reason why it raises ImportError.

If everything else fails, check this link:
http://www.b-list.org/weblog/2007/dec/04/magic-tags/