[Zope] Problem with Plone URL

I have userd Plone for content management for my company. Every time I request some thing the URL automatic incluse the Work Plone. http://mywwebsiet.com/Plone/Plone/Plone/Plone/Plone/Plone/Plone/Plone Could you show me how to sold this problem? How can I change the word Plone to another work?