Something is awry. The second slide in the filmstrip (Tira de pelicula) is selected, looks empty although the used master slide is completely different, has a blue and a grey part and a placeholder. It is a title master slide 2 from the theme Veracity which is the default them. Those parts should be visible in the small slide in the Filmstrip but that is not the case. The stage itself seems indeed not centered. and wonder why you don't have scrollbars at all.
Can you please clean the Preferences? Find the subfolder 'utils' (not sure of that name in your Spanish version) in the installation folder, and run CleanPreferences... fitting for your OS (Windows or Mac) while Captivate is closed.