It's not possible to modify a dict inside a dict using a manager from 
multiprocessing.

Ex:

from multiprocessing import Process,Manager

def f(d):
    d['1'] = '1'
    d['2']['1'] = 'Try To Write'

if __name__ == '__main__':
    manager = Manager()

    d = manager.dict()

    d['2'] = manager.dict()

    print d

    p = Process(target=f, args=(d,))
    p.start()
    p.join()

    print d

    d['2'] = 5
    print d

The output Under Windows 7 (32 Bits) / Python 2.6.2 (32 Bits) is:

{'2': {}}
{'1': '1', '2': {}}
{'1': '1', '2': 5}

The output is the same if you change "d['2'] = manager.dict()" to 
"d['2'] = dict()"

I get the same results on:
Python 2.6.2 (r262:71600, Sep 14 2009, 18:47:57)
[GCC 4.3.2] on linux2

I think this is the same issue I was seeing yesterday.  You can exercise
the issue and cause an exception with just 6 lines:

##### CODE #####
from multiprocessing import Manager
manager = Manager()
ns_proxy = manager.Namespace()
evt_proxy = manager.Event()
ns_proxy.my_event_proxy = evt_proxy
print ns_proxy.my_event_proxy

##### TRACEBACK #####
Traceback (most recent call last):
  File "test_nsproxy.py", line 39, in <module>
    print ns_proxy.my_event_proxy
  File "/usr/lib64/python2.6/multiprocessing/managers.py", line 989, in
__getattr__
    return callmethod('__getattribute__', (key,))
  File "/usr/lib64/python2.6/multiprocessing/managers.py", line 740, in
_callmethod
    raise convert_to_error(kind, result)
multiprocessing.managers.RemoteError:
---------------------------------------------------------------------
Unserializable message: ('#RETURN', <threading._Event object at 0x1494790>)
---------------------------------------------------------------------

Storing a proxy into a proxied object and then accessing the proxy 
returns a copy of the object itself and not the stored proxy.  Thus,
updates to the nested dict are local and do not update the real object,
and proxies to unpicklable objects raise an exception when accessed.

When a manager receives a message, it unpickles the arguments; this
calls BaseProxy.__reduce__, which calls RebuildProxy.  If we are in the
manager, this returns the actual object, otherwise it returns a new
proxy.  If we naively disable the ability for proxied objects to be
unredirected in the manager, as in the attached svn diff, this solves
the problem that Carlos and I are seeing.  Surprisingly, after applying
this change, the full multiprocessing regression test still runs fine. 
I'm sure this change should have some greater impact, but I'm not sure
what.  I would appreciate if someone more knowledgeable could comment.

Nothing jumps out to me off the top of my head - I can take a closer look 
at this after my pycon planning duties finish up in a few weeks. I agree 
this is unintended behavior. I'll need to audit the tests to make sure 
that A> This is being tested, and B> Those tests are not disabled.

When we included multiprocessing, some tests were deemed too unstable at 
the time, and we disabled. This was unfortunate, and I haven't been able 
to circle back and spend the time needed to refactor the test suite.

The tests for the SyncManager are being automagically generated at
import time -- I was not quite able to follow that well enough to know
exactly what is getting tested, or if they are even enabled.  It did not
appear to contain any recursion, however.

Yeah, the auto-generation is too clever and needs to be pulled out 
entirely.

Even with the patch, I can not resolve this problem. I can reproduce the problem with the patched version with the following code. My system is:

Python 2.6.4 (r264:75821M, Oct 27 2009, 19:48:32)
IPython 0.10
Platform is Mac OS X (10.5.8) Darwin Kernel Version 9.8.0: Wed Jul 15 16:55:01 PDT 2009

import multiprocessing as mp

def f(d):
  d['f'] = {}
  d['f']['msg'] = 'I am here'

manager = mp.Manager()
d = manager.dict()

p = mp.Process(target=f, args=(d,))

p.start()
p.join()

print d

d = {}
f(d)

print d

Output:

{'f': {}}
{'f': {'msg': 'I am here'}}

Kaushik, in your example, d is a dict proxy, so assignment to d['f'] correctly ferries the assignment (a new normal dict) to the d['f'] in the original process.  The new dict, however, is not a dict proxy, it's just a dict, so assignment of d['f']['msg'] goes nowhere.  All hope is not lost, however, because the Manager can be forked to new processes.  The slightly modified example below shows how this works:

from multiprocessing import Process, Manager
def f(m, d):
    d['f'] = m.dict()
    d['f']['msg'] = 'I am here'

m = Manager()
d = m.dict()
p = Process(target=f, args=(m,d))
p.start()
p.join()
print d
{'f': <DictProxy object, typeid 'dict' at 0x7f1517902810>}
print d['f']
{'msg': 'I am here'}

With the attached patch, the above works as shown, without, it gives the same output as your original example.

Hello,
Trying to share a dictionary of dictionaries of lists with a manager I get the same problem with the patch applied in Python 2.7 (r27:82500, Nov 24 2010, 18:24:29) [GCC 4.1.2 20080704 (Red Hat 4.1.2-48)] on linux2.

The shared variable in results and what I'm trying to do is simultaneously parsing multiple files.

The quality of the code is not very good because I'm a newbie python programmer.

Best regards,
Darío