You are seeing this error because the action adicionar is not defined in controller ComentariosController
If you want to customize this error message, create blog/views/errors/missing_action.thtml.
Fatal: Confirm you have created the ComentariosController::adicionar() in file : blog/controllers/comentarios_controller.php
<?php
class ComentariosController extends AppController {
function adicionar() {
}
}
?>