Constructor in custom controller?
I'm not a huge fan of it but for this situation it might be more appropriate to use init(), Looking at Craft\BaseController:

/**
 * Initializes the controller.  This method is called by the Craft before the controller starts to execute.
 *
 * @throws HttpException
 * @return null
 */
public function init()
{

}


It seems a little odd to me to have a constructor for a controller though, what is it you're doing in it? Yii's Controller filters might be a better fit.