spl_autoload_register Throws an Error in My Production Server

[eluser]Aken[/eluser]
First, what version of PHP is your production running? The anonymous function you're using is supported in 5.3+

The second error (Frontend_Controller not found) could be your autoload function not correctly loading the files necessary (which is just a guess). You might consider adding an include / require call directly in your MY_Controller file, or even add those classes to the file (you can add whatever classes you want, doesn't have to be only one - it's just normal PHP code here). You actually don't even need to name your class MY_Controller - just the file needs to be named that.