Rewrite Log:

(3) [perdir X:/www/w/] strip per-dir prefix: X:/www/w/index.php -> index.php
(3) [perdir X:/www/w/] applying pattern '^/W/$' to uri 'index.php'
(3) [perdir X:/www/w/] strip per-dir prefix: X:/www/w/index.php -> index.php
(3) [perdir X:/www/w/] applying pattern '^/wiki$' to uri 'index.php'
(3) [perdir X:/www/w/] strip per-dir prefix: X:/www/w/index.php -> index.php
(3) [perdir X:/www/w/] applying pattern '^/wiki/$' to uri 'index.php'
(3) [perdir X:/www/w/] strip per-dir prefix: X:/www/w/index.php -> index.php
(3) [perdir X:/www/w/] applying pattern '^/wiki/([.*])$' to uri 'index.php'
(1) [perdir X:/www/w/] pass through X:/www/w/index.php

.htaccess:
RewriteEngine On
RewriteRule ^/W/$ (index.php/Main_Page) [QSA]
RewriteRule ^/wiki$ (index.php?title=Main_Page) [QSA]
RewriteRule ^/wiki/$ (index.php?title=Main_Page) [QSA]
RewriteRule ^/wiki/([.*])$ (index.php?title=$1) [QSA]