You are seeing this error because the view /home/proyectos/zumex/www/app/views/lista_landings/ver.thtml for action ver in controller ListaLandings could not be found.
Notice: this error is being rendered by the app/views/errors/missing_view.thtml
view file, a user-customizable error page for handling missing/invalid views during rendering.
Fatal: Unable to load view file /home/proyectos/zumex/www/app/views/lista_landings/ver.thtml for action ListaLandingsController::ver()