A chap has collected a set of versions which work together well and comments say that its been used in Vista. The zip of all pytho bits are here:
http://www.deviantart.com/download/7..._resources.zip
and the version of Gimp it was checked with was here:
http://downloads.sourceforge.net/gim...i686-setup.exe
These are 32 bit apps and the instructions on how to install them are contained in the amusing named file:
IDIOTS NEVER READ THIS.txt
It seems like a completely different set of installs to that which you mentioned so give this one a go and see if it works.
Edit -- It mentions that you must install Gimp after python perhaps that is it.