1. Create Windows installer with Python 2.5 from attached project.
2. Install it with Python 2.6.1.
3. The post-installer will fail with error message: 
*** run_installscript: internal error 0xFFFFFFFF ***

The code causing this is:

import socket

and the actual error is:

ImportError
DLL load failed: The specified module could not be found.
  File "<string>", line 6, in windows_binary_install
  File "c:\apps\python26\lib\socket.py", line 46, in <module>
    import _socket

If the installer is created with Python 2.6.1, it works fine. 

The problem was noticed in the Robot Framework project and the issue can
be found from http://code.google.com/p/robotframework/issues/detail?id=196.

This problem was first asked as part of issue
http://bugs.python.org/issue4566, but Martin v. Löwis recommended to
open new issue for this.