[Zope] Invoking an executable from zope

Hi, I need to invoke an executable file from zope. I am not able to import modules like os or nt in python script. I also tried to use an external method, but am not able to do so. Zope hangs and I am not able to restart it without restarting the machine. Is there any built-in functions in python to accomplish this? Can we do this from zope itself?? Plz explain. Thanks and regards,