I choose DokuWiki to be my Wiki, but it doesn't support to create wiki farms [ http://en.wikipedia.org/wiki/Wiki_farm
I need to create a great number of wikis (wich wiki have your administrator, your users etc.) but install one to one will take me much time, and it's impossible to administrate.
To do this, I had some problems with this line: if(!defined('DOKU_INC')) define('DOKU_INC',realpath(dirname(__FILE__)).'/'); that is in MANY files.