ActionScript 3.0 :: Movie With Next / Previous Buttons Having Unique Function

I have a movie that uses a next and previous button. The next button works the same on every page calling a function that uses next(). The movie continues until it is told to stop. The previous button takes you directly to a specific frame in the movie. When running through and testing, if I go forward a frame and then back to the beginning and then add a frame every time, it seems to work fine. But if I go forward 3 times and back 2, or mix it up in any way, the previous button will only work once. Then after that you can go forward as much as you want, but you can only go back once. Each frame that has a previous button has a unique function.

Here is my code below:
stop();
import flash.ui.Keyboard;
import flash.events.KeyboardEvent;
stage.addEventListener(KeyboardEvent.KEY_DOWN, Next);
Next_btn.addEventListener(MouseEvent.CLICK, Next);
Previous_btn.addEventListener(MouseEvent.CLICK, Disclosure2);
[Code] .....