[Zope] zope stopped working suddenly

Greetings First , I am glad to join you at this list. I installed Zope on Fedora Core 6, and started to learn how to use it. for a few days i was able to access the management interface (ZMI) through http://127.0.0.1:8080 after starting zope through .../zopectl start. but as a sudden I found myself unable to enter to the ZMI anymore. The browser displays an error as if zope is not started at all. I am a newbie in both Linux and Zope, so please can anyone pass me some tips on how to check what is causing the problem and how to solve it? I searched the internet for two weeks now, but there is no hint about the problem!! Sincerely Yours, Zope Beginner (0.0.1.1)