A third kind of error:

http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.x/builds/5992/steps/test/logs/stdio

======================================================================
ERROR: test_import (test.test_pickle.CompatPickleTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\test_pickle.py", line 241, in getmodule
    return sys.modules[module]
KeyError: 'multiprocessing.popen_fork'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\test_pickle.py", line 266, in test_import
    getmodule(module)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\test\test_pickle.py", line 243, in getmodule
    __import__(module)
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\multiprocessing\popen_fork.py", line 13, in <module>
    class Popen(object):
  File "C:\buildbot.python.org\3.x.kloth-win64\build\lib\multiprocessing\popen_fork.py", line 25, in Popen
    def poll(self, flag=os.WNOHANG):
AttributeError: module 'os' has no attribute 'WNOHANG'