[Zope] zombies with htmldoc

Running htmldoc via an External Method that uses popen2() under zope 2.6.2b3 and python 2.1.3 (both by the book...) I get zombie processes that just hang in there... Now zombie processes exist when a parent does not wait() for a child, so the problem would look like it's in popen(). The htmldoc process seems to run to completion and generate the expected output. I seem to remember there were problems with popen, but a quick browse of the python bug list didn't turn up anything. Anyone else seen this behavior? Oh, yes -- the OS is RH9 and the machine is a dual processor Athlon. I suspect some OS related problem since this same code works without creating Zombies on RH7.3.