ActionScript 2.0 Button stops working

I have created a movieclip called service1. When you click on a button on the main timeline, the service1 mc pops up. Within the service1 mc is a button that, when pressed, closes the service1 mc window. The code that I have placed on the button is:

on(press){
this._visible = false;
}

When I test the scene the button does exactly what I want it to do, the service1 mc dissapears. Perfect! However, when I test the movie, the service1 mc pops up but the button goes inactive. Can anyone tell me why and how do I fix it?