I went through this example here:
http://docs.celeryproject.org/en/latest/django/first-steps-with-django.html
All my tasks are in files called tasks.py.
I got the same error.
Seems that from __future__ import absolute_import DOES NOT work for Python 2.6.1, still not raising an error.
from __future__ import absolute_import
Upgraded to Python 2.7.5 and it just worked.