As I reported in
http://mail.python.org/pipermail/distutils-sig/2008-April/009398.html
easy_install on a 64 bits Python on a 64 bits Windows is broken in that it gives
the following error:

Cannot find Python executable C:\Python25\python.exe

I believe that due to cli.exe and gui.exe (built from launcher.c) being 32-bits
executables they are trying to use 32-bit specific calls which fail on a 64 bits
Windows.
As Mark Hammond said in
http://mail.python.org/pipermail/distutils-sig/2008-May/009462.html: "I suspect
that the issue is that a 32bit cli.exe or gui.exe is attempting to LoadLibrary a
64bit executable and failing (specifically, loadable_exe() in launcher.c)"