This is under a Windows 7 VM. I don't understand what the assertion means:

Z:\>__svn__\PCbuild\amd64\python_d.exe -m test -v test_multiprocessing
== CPython 3.2b2+ (py3k, Jan 6 2011, 10:56:48) [MSC v.1500 64 bit (AMD64)]
==   Windows-7-6.1.7600 little-endian
==   Z:\__svn__\build\test_python_1360
Testing with flags: sys.flags(debug=0, division_warning=0, inspect=0, interactiv
e=0, optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0, ignore_enviro
nment=0, verbose=0, bytes_warning=0, quiet=0)
[1/1] test_multiprocessing
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 369, in main
    prepare(preparation_data)
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 477, in prepare
    assert main_name not in sys.modules, main_name
AssertionError: __main__
[49434 refs]
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 369, in main
    prepare(preparation_data)
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 477, in prepare
    assert main_name not in sys.modules, main_name
AssertionError: __main__
[49434 refs]
test test_multiprocessing crashed -- <class 'EOFError'>:
Traceback (most recent call last):
  File "Z:\__svn__\lib\test\regrtest.py", line 969, in runtest_inner
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 369, in main
    indirect_test()
  File "Z:\__svn__\lib\test\test_multiprocessing.py", line 2102, in test_main
    prepare(preparation_data)
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 477, in prepare
    assert main_name not in sys.modules, main_name
AssertionError: __main__
    ManagerMixin.manager.start()
  File "/home/antoine/py3k/__svn__/Lib/multiprocessing/managers.py", line 531, i
n start
[49434 refs]
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 369, in main
    self._address = reader.recv()
EOFError
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    prepare(preparation_data)
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 477, in prepare
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 369, in main
1 test failed:
    assert main_name not in sys.modules, main_name
AssertionError: __main__
    prepare(preparation_data)
  File "Z:\__svn__\lib\multiprocessing\forking.py", line 477, in prepare
[49434 refs]
    assert main_name not in sys.modules, main_name
AssertionError: __main__
[49434 refs]
    test_multiprocessing
Traceback (most recent call last):
  File "Z:\__svn__\lib\test\support.py", line 468, in temp_cwd
    yield os.getcwd()
  File "Z:\__svn__\lib\test\__main__.py", line 13, in <module>
    regrtest.main()
  File "Z:\__svn__\lib\test\regrtest.py", line 708, in main
    sys.exit(len(bad) > 0 or interrupted)
SystemExit: True