[Zope] permission to do execv()

hi all: I'm a newbie to Zope. As my DTML doc called python script , a permission problem occured. I was prompted to key in username/passwd, but I had no idea which account I shall use. I used the function os.execv() in my script , but the function failed to execute because I was unauthorized. The following is the error message: Zope Error Zope has encountered an error while publishing this resource. Error Type: Unauthorized Error Value: You are not allowed to access execv in this context How can I get rid of this problem? Any suggestion would be appreciate ：）