How do I...Troubleshoot 'Not Found 404' for index.php?

This is usually caused by not having the mod_rewrite module setup properly in apache.  DekiWiki uses mod_rewrite to make "friendly" Urls like /Home instead of index.php?title=Home.  To enable mod_rewrite on Debian, do the following:

Note: other linux distributions will have a different mechanism for enabling mod_rewrite

a2enmod rewrite
/etc/init.d/apache2 restart