removeChild(getChildByName("backButton")); //help please

programming flash
1

hi!

i added a display object like so:


var backButton:BtnSMenu = new BtnSMenu();
backButton.name = "backButton";
mainHolder.parent.parent.parent.addChild(backButton);

but then later in the code i want to remove the child so i did this:


mainHolder.parent.parent.parent.removeChild(getChildByName("backButton"));

but i get this error:
TypeError: Error #2007: Parameter child must be non-null.

do you know what i am doing wrong here?

thanks for any help!