probleme : navigate between swf

hi, i have 3 project (A,B,C), I use the folowing code to navigate between them  ( the project start with A, then i navigate to B its work, also if i want to return from B to A its work, But if i want to go from B to C it doesn't work , )

I'm into project A and i want to go in project B      ===>  No probleme its work good

// go to B

unité77.addEventListener(MouseEvent.CLICK,h_aller_exercices);

function h_aller_exercices(event:MouseEvent):void

{

  var ex5_s:URLRequest=new URLRequest("division/B.swf");

  var ex5_l:Loader=new Loader();

  ex5_l.load(ex5_s);

  addChild(ex5_l);

}

// ( I m in B)  return from B to A    ===>  No probleme its work good

acc10.addEventListener(MouseEvent.CLICK,home10);

function home10(event:MouseEvent):void

{

  var h10_s2:URLRequest=new URLRequest("../A.swf");

  var h10_l2:Loader=new Loader();

  h10_l2.load(h10_s2);

  this.parent.removeChild(this);

  addChild(h10_l2);

}

now I'm in project B and I want to go in project C

controle.addEventListener(MouseEvent.CLICK,cont1);

function cont1(event:MouseEvent):void

{

  var h1_s2:URLRequest=new URLRequest("../evaluation/C.swf");

  var h1_l2:Loader=new Loader();

  h1_l2.load(h1_s2);

  addChild(h1_l2);

}