[Zope] IOError: [Errno 13] Permission denied (Zope 2.7.3)

I installed python 2.3.4 and then zope 2.7.3 from source and ran mkzopeinstance.py, but am experiencing a problem with privileges. I gather that I have to change some, but I do not know exactly how to do that. I have looked at http://www.plope.com/Books/2_7Edition/InstallingZope.stx And this post: http://www.gossamer-threads.com/lists/zope/users/177930 ...but am no clearer. Runzope results in: IOError: [Errno 13] Permission denied: '/home/mdl/zope-instance/var/Data.fs.lock ' Also, is there any special procedure for removing an instance? thanks again,