OSX again! Just when I finally got it to work nice on 64bit OSX then ofc 32bit starts to mess up. Good news is I started on a new job just before the summer and here I have a OSX workstation, so this time I hope I will be able to better troubleshoot and fix this problem
I first tried compiling and running with the default python (OSX 10.7.4 and python 2.7 64bit) and it worked just fine. I tried force this python to run in 32bit mode with arch, but that doesnt seem to work? Anyway, I downloaded the latest 2.7 python from python.org and then redid the whole thing with python-32, and then I get the same behavior as you.
I will do some experiments to see if I can figure out a solution, but as I only have access to OSX while Im at work and I mostly do work when Im there it might take a little bit of time
I will keep you updated when I find something.
http://www.pymunk.org - A python library built on top of Chipmunk to let you easily get cool 2d physics in your python game/app