Chokes on GETPPID

[Ben Ocean]

Hi;
I'm trying to install Zope and it chokes in this block:
 >>>
if not READ_ONLY:
     pf = open(PID_FILE, 'w')
     pid=str(os.getpid())
     try: pid=str(os.getppid())+' '+pid
     except: pass
     pf.write(pid)
     pf.close()
<<<
It specifically identified the *try* statement as the choke-point. How do I 
trouble-shoot this?
TIA,
BenO