I've found the problem: For the windows Python 3.1.1 x86 installation, the file \Python31\Lib \Distutils\command\build_ext.py, has this:
Line 313: self.compiler = new_compiler(compiler=None, But Python 2.6 has this line: Line 306: self.compiler = new_compiler(compiler=self.compiler, I've changed the Python 3.1.1 \Python31\Lib\Distutils\command \build_ext.py, Line 313 to this: self.compiler = new_compiler(compiler=self.compiler, And now MinGW gets properly called in Python 3.1.1. I think this must have been a typo. Is there anyone else that can confirm this? The installation that distributes the file with that line is from this Python ftp link: http://python.org/ftp/python/3.1.1/python-3.1.1.msi -- http://mail.python.org/mailman/listinfo/python-list