Celery Получено незарегистрированная задача типа (пример запуска)

I Я пытаюсь запустить пример из документации Celery.

Я запускаю: celeryd --loglevel=INFO

/usr/local/lib/python2.7/dist-packages/celery/loaders/default.py:64: NotConfigured: No 'celeryconfig' module found! Please make sure it exists and is available to Python.
  "is available to Python." % (configname, )))
[2012-03-19 04:26:34,899: WARNING/MainProcess]  

 -------------- celery@ubuntu v2.5.1
---- **** -----
--- * ***  * -- [Configuration]
-- * - **** ---   . broker:      amqp://guest@localhost:5672//
- ** ----------   . loader:      celery.loaders.default.Loader
- ** ----------   . logfile:     [stderr]@INFO
- ** ----------   . concurrency: 4
- ** ----------   . events:      OFF
- *** --- * ---   . beat:        OFF
-- ******* ----
--- ***** ----- [Queues]
 --------------   . celery:      exchange:celery (direct) binding:celery

tasks.py:

# -*- coding: utf-8 -*-
from celery.task import task

@task
def add(x, y):
    return x + y

run_task.py:

# -*- coding: utf-8 -*-
from tasks import add
result = add.delay(4, 4)
print (result)
print (result.ready())
print (result.get())

В той же папке celeryconfig.py:

CELERY_IMPORTS = ("tasks", )
CELERY_RESULT_BACKEND = "amqp"
BROKER_URL = "amqp://guest:guest@localhost:5672//"
CELERY_TASK_RESULT_EXPIRES = 300

Когда я запускаю "run_task.py" :

на консоли python

eb503f77-b5fc-44e2-ac0b-91ce6ddbf153
False

ошибки на сервере celeryd

[2012-03-19 04:34:14,913: ERROR/MainProcess] Received unregistered task of type 'tasks.add'.
The message has been ignored and discarded.

Did you remember to import the module containing this task?
Or maybe you are using relative imports?
Please see http://bit.ly/gLye1c for more information.

The full contents of the message body was:
{'retries': 0, 'task': 'tasks.add', 'utc': False, 'args': (4, 4), 'expires': None, 'eta': None, 'kwargs': {}, 'id': '841bc21f-8124-436b-92f1-e3b62cafdfe7'}

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/celery/worker/consumer.py", line 444, in receive_message
    self.strategies[name](message, body, message.ack_log_error)
KeyError: 'tasks.add'

Пожалуйста, объясните, в чем проблема.