Removing child from stage when new button clicked

1

I have an image map with hotspots that animate when clicked and bring up info onto the stage.
My problem today is how to stop the animation and remove the info on one button when a second button is clicked.
The info is intended to appear in a space to the side of the image map.

MY code works apart from it throws up an error when user clicks on the hotspot.

ArgumentError: Error #2025: The supplied DisplayObject must be a child of the caller.
at flash.display::DisplayObjectContainer/removeChild()
at helicopterHotspots2_fla::MainTimeline/showNoseInfo()

I’m pretty sure that there is a more elegant way of doing this, particularly as there will be ten buttons overall.

var mytestButt = new testButt();
var mytailInfo = new tailInfo_mc();
var myNewPulse = new myPulse();

var myNoseButt = new testButt();
var myNoseInfo = new noseInfo_mc();
var myNosePulse = new myPulse();

mytestButt.x = 65;
mytestButt.y = 174;
mytailInfo.x = 625;
mytailInfo.y = 174;
myNewPulse.x = 65;
myNewPulse.y = 174;

myNoseButt.x = 450;
myNoseButt.y = 200;
myNoseInfo.x = 625;
myNoseInfo.y = 174;
myNosePulse.x = 450;
myNosePulse.y = 200;

addChild(mytestButt);
addChild(myNoseButt);

mytestButt.addEventListener(MouseEvent.CLICK, showTailInfo);
myNoseButt.addEventListener(MouseEvent.CLICK, showNoseInfo);

function showTailInfo(event:MouseEvent):void
{
    trace("this is the tail");
    addChild(mytailInfo);
    addChild(myNewPulse);
    removeChild(myNosePulse);
    removeChild(myNoseInfo);
    
    }
    
    function showNoseInfo(event:MouseEvent):void
{
    trace("this is the nose");
    addChild(myNoseInfo);
    addChild(myNosePulse);
    removeChild(myNewPulse);
    removeChild(mytailInfo);
    }