[Problème] 404 - Component not found (joomla 3 back office)

This article is for joomla components / modules developers.
Usually you have this error when trying to run/configure your joomla 2.5 component on joomla 3.x plateform.
This error is due to non 100% compatibility of 2.5 components with joomla 3.x
For some simple components proceed as follows :

1. In every file that references DS variable
   put at the begin :
   if(!defined('DS')) define('DS', DIRECTORY_SEPARATOR);
2. rename admin.your_component.php file in admin section to your_component.php
3. Change each JController or JView classes reference to JControllerLegacy or JViewLegacy
4. Don't forget to do that to the 2 sections site and admin

This link may be useful

http://docs.joomla.org/Potential_backward_compatibility_issues_in_Joomla_3.0_and_Joomla_Platform_12.1