Parent controller is removed from the module tree

Hello,

I’m a newbie in this list. And Ive just begun using the Rails Engin
plugin.

I’m using a plugin’s controller, which is a child class of
“Admin::AdminController”.
When I reload the page. Rails causes a error which says,
“A copy of Admin::AdminController has been removed from the module
tree but is still active!”
How can I solve the problem?

Andy Matsubara