subprocess.getoutput does not currently work at all on Windows.
So it's not necessary to maintain backwards compatibility.

The following fix works for me on WinXP/Python 3.2.2.

Replace

    pipe = os.popen('{ ' + cmd + '; } 2>&1', 'r') # line 613 of subprocess.py

with

    if mswindows:
        pipe = os.popen(cmd + ' 2>&1', 'r') # Windows does not support { }
    else:
        pipe = os.popen('{ ' + cmd + '; } 2>&1', 'r')