I recently had an issue with a rails app working fine locally under rails 2.3.2 but failing when deployed to Media Temple’s Grid Service.

I got the error:

custom_require.rb:31:in `gem_original_require’: no such file to load — application (MissingSourceFile) etc etc

This turned out to be due to this change in the rails core. the previous application controller class ApplicationController, was kept in application.rb in the controllers folder. This is of course inconsistent, so they moved it to application_controller.rb.

To Fix, rename your application_controller.rb to application.rb

I’m not sure why Media Temple’s Rails 2.3.2 is different from mine, but anyway, perhaps this will help someone out.