ActionScript 3.0 :: How To Make Ball Walk To Box And Pickup Item

I have code that I wrote(myown and tutorials) and I am having some issues. The object is to make the ball walk to the box and pick up the item. When the pick up occurs the item(box) needs to disappear.

mcMain is the character(ball)
mcCoin is the item(square)

Code:
Variables for key downs
var leftKeyDown:Boolean = false; //left key down false
var upKeyDown:Boolean = false; //up key down false
var rightKeyDown:Boolean = false; //right key down false
var downKeyDown:Boolean = false; //down key down false
var mainSpeed:Number = 7; // speed of character
[Code] .....