Navigation buttons won't stop looping

I am building a site for some people that want a menu of links to pop out at the side of 3 main buttons. I thought I figured it out by using a tutorial in a book but it is definitely not working. The navigation shows when it shouldn’t and loops. Here is the link to my page:

http://www.gobrowncow.com/hannah/engulf/engulf.html

the swf:
http://www.gobrowncow.com/hannah/engulf/engulf.swf

the code the book told me to use for each movie which contains the nav menu
:
stop();
function buttonClick(event:MouseEvent):void
{
gotoAndStop(event.target.name);

project.enabled = true;
gear.enabled = true;

event.target.enabled = false;

}
project.addEventListener(MouseEvent.CLICK, buttonClick);
gear.addEventListener(MouseEvent.CLICK, buttonClick);

error message: function buttonClick(event:MouseEvent):void

Please help me out, I don’t know that much about flash but this is one feature my client insists upon and it would be good to know how to do it. Thanks!