Problems with Next and Back Buttons ActionScript 3.0

Hi,

I have set up a Back, Play and Next buttons in a slideshow I am making.  The next and back buttons work correctly until it gets to the end. 

If I press the Next button it goes back to what appears to be Frame 1 and will not go to the next slide. If I press the Back button it will then go to Frame 201 and If I press next again it will go to Frame 1.  It will only go back and forth in between those frames.

If I press the Back button from the beginning it goes through the slide show correctly then it gets stuck at Frame 1.  If I press next button it goes to Frame 121 and gets stuck in between 121 and 1.

I can't figure this out please help.

My code on Frame 1 is:

stop();

play_btn.addEventListener(MouseEvent.CLICK,playslideshow);

function playslideshow(event:MouseEvent) { gotoAndPlay(2); }

forward_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_2);

function fl_ClickToGoToAndStopAtFrame_2(event:MouseEvent):void

{

  gotoAndStop(40);

}

back_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_8);

function fl_ClickToGoToAndStopAtFrame_8(event:MouseEvent):void

{

  gotoAndStop(281);

}

My code on Frame 40 is:

forward_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_7);

function fl_ClickToGoToAndStopAtFrame_7(event:MouseEvent):void

{

  gotoAndStop(121);

}

back_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_9);

function fl_ClickToGoToAndStopAtFrame_9(event:MouseEvent):void

{

  gotoAndStop(1);

}

My code on Frame 121 is:

forward_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_3);

function fl_ClickToGoToAndStopAtFrame_3(event:MouseEvent):void

{

  gotoAndStop(201);

}

back_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_10);

function fl_ClickToGoToAndStopAtFrame_10(event:MouseEvent):void

{

  gotoAndStop(40);

}

My code on Frame 201 is:

forward_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_4);

function fl_ClickToGoToAndStopAtFrame_4(event:MouseEvent):void

{

  gotoAndStop(281);

}

back_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_11);

function fl_ClickToGoToAndStopAtFrame_11(event:MouseEvent):void

{

  gotoAndStop(121);

}

My code on Frame 281 is:

forward_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_5);

function fl_ClickToGoToAndStopAtFrame_5(event:MouseEvent):void

{

  gotoAndStop(1);

}

back_btn.addEventListener(MouseEvent.CLICK, fl_ClickToGoToAndStopAtFrame_12);

function fl_ClickToGoToAndStopAtFrame_12(event:MouseEvent):void

{

  gotoAndStop(201);

}