from Thiebaut Champenier "python wo_pcgi.py" doesn't build the extensions correctly due to linking problems. To fix it, I just SymLinked ld_so_aix, makexp_aix and python.exp (found in /Modules/) into each of the dirs in /python/lib that contain .c files... and it worked just great. But I'm sure it's not the best solution from Wolfgang Roesner (reporting segfaults and a fix) The default stack size for a pthread on AIX (at least in my configuration) is 96kB. On Solaris it's 1M. As soon as I explicitly set the initial stack size to 1M the problem went away and it appears as if Zope is up and running. Unfortunately I really had to change "thread_pthread.h" in Python which obviously is not a nice thing to do as I now have a need for my own private version of Python. But at least I have a running version of Zope on AIX.