[mod_python] Trouble spawning a long running process...

Hi all,

I'm attempting to spawn a process in my mod_python function.  I want to run a 
long-running script in a seperate process while returning the process id to 
the client quickly.  However, the spawned process goes zombie (defunct), I 
think when the mod_python function finishes sending the response to the 
client.  Here's how I'm spawning the process:
process_id = os.spawnl(os.P_NOWAIT, BUILDISO_COMMAND)
and when I check the status of the spawned process:
# ps ax
[...]
 4229 ?        S      0:00 /usr/sbin/httpd
 4237 ?        Z      0:00 [httpd] <defunct>
It is defunct.  (The parent is dead, long live the parent!)

Do any of you have advice for a good way to keep the user from having to wait 
for long processes to finish before seeing a response from mod_python?

I'm running Fedora Core 2, mod_python-3.1.3-1, python 2.3.3, apache 2.0.49
I'm not sure if it matters, but my .htaccess file for this little app contains 
only:
AddHandler python-program .py
PythonHandler mod_python.publisher
PythonDebug On

As a bit of background, the spawned script is creating an iso file approx 45MB 
for the client to download (later).  I have it working using:
commands.getstatusoutput(BUILDISO_COMMAND)
but that makes the user wait until the child process is complete.  I just want 
to keep the user from having to stare at a an empty, spinning browser while 
the iso is built.

Many thanks for your time, wisdom and suggestions.

Best regards,

Eric.