Joomla autoloader issue

A more detailed description that someone else made is here: http://forum.civicrm.org/index.php/topic,5155.html

A patch has been promised two years ago and nothing has been done since then, we have just had a customer upgrade to newest CiviCRM and the same error happened.

If I may give you some advance on completing this task: the loader.php file that you're patching also contains a JLoader class which has a method called Register. It allows you to register arbitrary class names and their mappings to files. More on this topic in the API docs: http://api.joomla.org/Joomla-Framework/JLoader.html#register

Please fix this because patching Joomla core is not really an option. While it may work on personal LAMP servers, the world now goes towards more sophisticated applications, so using API instead of hacking files is essential.