Follow the directions here.
http://gaim.sourceforge.net/win32/index.php#portable
The GTK directory is actually Program Files\Common Files\GTK\2.0\
If you want to add the upx compressions go here http://upx.sourceforge.net/ and download and just use that program to compress the dll files and the exe files.
This works for me, the version still says 2.13 but it has all of the other files from Gaim 2.00b5 as is noticable by going to teh plugins and looking at teh versions