Celery: linked task throws connection error - celery

Question

I tried to run a very simple task with a linked task mentioned in the tutorial
add.apply_async((2, 2), link=add.s(16))
and got an exception in the worker process:
[2014-09-21 19:56:38,531: WARNING/Worker-1] C:\Python33\lib\site-packages\celery-3.1.15-
py3.3.egg\celery\app\trace.py:364: RuntimeWarning: Exception raised outside body: OSError(ConnectionRefusedError(10061, 'No connection could be made because the target machine actively refused it', None, 10061),):
Traceback (most recent call last):
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\utils\__init__.py", line 420, in __call__
return self.__value__
AttributeError: 'ChannelPromise' object has no attribute '__value__'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\connection.py", line 436, in _ensured
return fun(*args, **kwargs)
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\messaging.py", line 173, in _publish
channel = self.channel
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\messaging.py", line 190, in _get_channel
channel = self._channel = channel()
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\utils\__init__.py", line 422, in __call__
value = self.__value__ = self.__contract__()
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\messaging.py", line 205, in <lambda>
channel = ChannelPromise(lambda: connection.default_channel)
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\connection.py", line 756, in default_channel
self.connection
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\connection.py", line 741, in connection
self._connection = self._establish_connection()
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\connection.py", line 696, in _establish_connection
conn = self.transport.establish_connection()
File "C:\Python33\lib\site-packages\kombu-3.0.23-py3.3.egg\kombu\transport\pyamqp.py", line 112, in establish_connection
conn = self.Connection(**opts)
File "C:\Python33\lib\site-packages\amqp-1.4.6-py3.3.egg\amqp\connection.py", line 165, in __init__
self.transport = self.Transport(host, connect_timeout, ssl)
File "C:\Python33\lib\site-packages\amqp-1.4.6-py3.3.egg\amqp\connection.py", line 186, in Transport
return create_transport(host, connect_timeout, ssl)
File "C:\Python33\lib\site-packages\amqp-1.4.6-py3.3.egg\amqp\transport.py", line 299, in create_transport
return TCPTransport(host, connect_timeout)
File "C:\Python33\lib\site-packages\amqp-1.4.6-py3.3.egg\amqp\transport.py", line 95, in __init__
raise socket.error(last_err)
OSError: [WinError 10061] No connection could be made because the target machine actively refused it
I did a brief debugging in transport.py and found the worker was trying to connect to port 5672 on localhost. It seems that the worker thinks the linked task needs to be executed via local RabbitMQ instance. This is weird because I specified a remote RabbitMQ broker in the configuration setting. Also the setting works if I simply run the async call without a linked task:
add.apply_async((2, 2))
Here is my setup:
Use RabbitMQ as broker and Redis as results back end on a remote Windows Server
Run my test client on another windows 7 machine
Can anyone shed some light? Thanks.