New to flash...pls help!

I’m working on an audio slide show presentation with multiple scenes. I’ve created buttons and I’m trying to write the action script to make each button go to it’s cooresponding scene. I keep getting the following error message, which prevent my movie from playing:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at flowershowflash_fla::MainTimeline/frame1()

Here is the code in my actions, which are on frame one, scene one:

flower1_btn.addEventListener(MouseEvent.CLICK, scene2);
flower2_btn.addEventListener(MouseEvent.CLICK, scene3);
flower3_btn.addEventListener(MouseEvent.CLICK, scene4);
flower4_btn.addEventListener(MouseEvent.CLICK, scene5);
flower5_btn.addEventListener(MouseEvent.CLICK, scene6);

function scene2(Event)
{
gotoAndPlay(1, “Scene 2”);
}

function scene3(Event)
{
gotoAndPlay(1, “Scene 3”);
}

function scene4(Event)
{
gotoAndPlay(1, “Scene 4”);
}

function scene5(Event)
{
gotoAndPlay(1, “Scene 5”);
}

function scene6(Event)
{
gotoAndPlay(1, “Scene 6”);

Any help would be greatly greatly appreciated.