X is not missing constant Y

Hi!
I have an engine that adds functionallity to two namespaces with two
different controllers

EngineName::Controller
EngineName::Admin::Controller

When I try to access an action that routes to
EngineName::Admin::Controller I received an error saying
EngineName::Controller doesn't have the requested action. Then of
course I thought the routing was going to the wrong controller.

Checked the rake routes and it was correctly routing to 'engine_name/
admin/controller#action'

Tried just loading the constant in the console of the application and
that's where I got the error of the mail's subject

on the first time:

EngineName::Admin::Controller

=> EngineName::Controller

not being weird enough, when repeating the same line again I got the
error:

ArgumentError: EngineName is not missing constant Controller!

The engine is simple enough, on the app/controllers folder I have the
controller.rb and the admin/controller.rb
My env is currently ruby 1.9.2, tested this with rails 3.0.6 and 3.0.7