Help please error 1180 and potentially null objects, ect

1

Using this code I get these dreaded errors:
Scene 1, Layer ‘Actions’, Frame 61, Line 5 1180: Call to a possibly undefined method Worm.
and
Scene 1, Layer ‘Actions’, Frame 61, Line 6 1180: Call to a possibly undefined method Killer.

I have the feeling I need to make classes and have separate .as files for worm and killer but am not sure if I can solve this problem without this as I am not sure how to make classes(I have very basic as3 understanding and am not trying to be lazy)

Is there something someone can suggest that I 1) learn how to make classes for these and a reference for info on that or 2) I don’t need to and its just something simple I am missing?

[AS]
import flash.display.MovieClip;
import flash.events.Event;

// instantiate Killer and Worm instances from the library
var worm:MovieClip = new Worm();
var killer:MovieClip = new Killer();

// position worm
worm.x = 200;
worm.y = -50;

// not sure where killer is supposed to be
killer.x = stage.stageWidth/2 - killer.width/2;
killer.y = stage.stageHeight/2 - killer.height/2;

// add killer and worm to the displaylist
addChild(worm);
addChild(killer);

var speed:Number = 5;
var movement:Number = 5;

addEventListener(Event.ENTER_FRAME, descent);

function descent(e:Event):void
{
worm.y += speed;

// worm exit test
if ( worm.y >= 635 )
{
    removeEventListener(Event.ENTER_FRAME, descent);
}

// mouseX test
if ( mouseX > worm.x + 5 )
{
    worm.x += movement;
}
else if (mouseX < worm.x - 5)
{
    worm.x -= movement;
}
else
{
    worm.x = mouseX;
}

// worm collision test
if ( worm.hitTestObject(killer) )
{
    removeChild(worm);
    removeEventListener(Event.ENTER_FRAME, descent);
    gotoAndPlay(237);
}

}
[/AS]

It is a game where the parachutes(falls down) and the player moves the mouse and the worm avoids hitting the fish(killer) and lands on the island winning the game. I had no problems getting the worm to listen to me and what it says in the code until I placed the hitTest in then I tried this approach of naming them movieclips…before my problem was they were null.
Any help or suggestions would be much appreciated.