They are not entirely different. The resolution refers to that point when the conflict within the story is resolved. This happens in stages in "The Cask of Amontillado." The main conflict involves the insult Montressor feels he has endured from Fortunato. This conflict is resolved(for the most) when we realize Montressor's plan for revenge and the details of how it will be accomplished, i.e. chaining him to the wall and beginning to brick him in. The outcome of the story is the death of Fortunato, which never occurs in the story and we can only infer as readers. This would explain how they are different. One occurs within the story, the other does not.