[Zope] a problem with 'start' command

hi all, I am a starter with Zope and i have a simple question. I need to execute 'start' command to start the server again. when i tried to do it, it gives me the message: command not found I looked at the directory, i can find the start command, and the permissions are -rwx--x--x. Can somebody help me with this ? Thanks Gaby