Can't localize GTK+ itself on Windows XP

[Andrew Ziem <ahz001 gmail com>]

I can't get GTK+ to localize its own strings when I bundle it and install it
on another Windows machine.  On my development machine, it is fine.  On a
clean test machine, only my application's own strings are localized, but the
GTK+ about dialog and file open dialogs are in English.

I think I have the directory layout right:
C:\Program Files\BleachBit\bin\bleachbit.exe
C:\Program Files\BleachBit\bin\libgtk-win32.dll
C:\Program Files\BleachBit\share\locale\es\LC_MESSAGES\gtk20.mo
C:\Program Files\BleachBit\share\locale\es\LC_MESSAGES\bleachbit.mo

Here is a detailed file layout (with redundant copies of 'share' for
testing):
http://pastebin.com/m38d517f2

I tried setting the language two ways
1. Control Panel - Regional and Language Options - Standards and Formats
2. environment variable: set LANG=es_ES

My environment
* GTK 2.16.4 from binaries at http://www.gtk.org/download-windows.html
* Python 2.5.4
* PyGTK 2.12
* Executables compressed with UPX
* Windows XP SP3
* NSIS 2.45

My source code
http://bleachbit.svn.sourceforge.net/viewvc/bleachbit/trunk/bleachbit/


Andrew