Investigating the issue #6716 I reported earlier, I've been trying to
build Windows MSI installer package of Python 3.1 on my own.
I checked out the svn source, built things with Visual C++ 2008 Express
Edition, and tried to make MSI package in Tools\msi directory.
When I run Tools\msi\msi.py in Tools\msi directory, the following error
occurs:

Traceback (most recent call last):
  File "msi.py", line 178, in <module>
    if msilib.pe_type(dll_path) != msilib.pe_type("msisupport.dll"):
  File "E:\python31svnbuild\Tools\msi\msilib.py", line 665, in pe_type
    header = open(path, "rb").read(1000)
IOError: [Errno 2] No such file or directory: 'msisupport.dll'

It seems that msilib.pe_type("msisupport.dll") is called before
msisupport.dll is created.
I read msi.py and learned that msilib.pe_type("msisupport.dll") (line
178) is executed before os.system("nmake /nologo /c /f msisupport.mak")
(line 372) is executed in add_ui(), which is called at line 1299.
So I made a patch to make msi.py to see if the file "msisupport.dll"
exists, and if it does, check if the dll is for the correct architecture.