Probelm triggering a mouseOut event

I have a button on the stage, that plays a movie clip when the user hovers over the button, and stops the movie clip when the user moves the mouse off of the button.

To do this I obviously set up two event listeners (over and out).

I then set up a third event listener (down) so that the user can click and it will take the user to another frame in the timeline (where this button does not exist).

The problem I have, is that when I click the button, and jump to another frame, the button dissapears, and therefore triggers the buttons Out event, which trys to stop a movieclip that is no longer on the stage and I get an error.

How can I stop the Out event triggering when I click on the button and move elsewhere in the timeline??