TypeError: Error #1009: Cannot access a property or method of a null object reference.

As said in the title, i have an error of #1009 and i do not know how to fix it

the full error is:

TypeError: Error #1009: Cannot access a property or method of a null object reference.

    at project_fla::MainTimeline/dragandStop()

import flash.events.MouseEvent;
import flash.events.Event;
import flash.display.MovieClip;
stop();
var foodArray:Array = new Array(Apple, Burger, Carrot, Milk, Pizza, Water);
var foodOnStage:Array = new Array();
var foodCollected:int = 0;
var foodLost:int = 0;
for (var i:int = 0; i <50; i++)
{
    var pickFood = foodArray[int(Math.random() * foodArray.length)];
    var food:MovieClip = new pickFood();
    addChild(food);
    food.x = Math.random() * stage.stageWidth;
    food.y = Math.random() * -500;
    food.speed = Math.random() * 15 + 5;
    foodOnStage.push(food);
}
basket_mc.addEventListener(MouseEvent.MOUSE_DOWN, dragBasket);
function dragBasket(evt:Event):void
{
    basket_mc.startDrag();
}
stage.addEventListener(MouseEvent.MOUSE_UP, dragandStop);
function dragandStop(evt:Event):void
{
    basket_mc.stopDrag();
}
stage.addEventListener(Event.ENTER_FRAME, catchFood);
function catchFood(evt:Event):void
{
    for (var i:int = foodOnStage.length-1; i > -1; i--)
    {
        var currentFood:MovieClip = foodOnStage;
        currentFood.y += currentFood.speed;
       
        if (currentFood.y > stage.stageHeight - currentFood.height)
        {
            currentFood.y = 0 - currentFood.height;
            foodLost++;
            field2_txt.text = "Total Food Lost: " + foodLost;
        }
        if (currentFood.hitTestObject(basket_mc))
        {
            foodCollected++;
            removeChild(currentFood);
            field1_txt.text = "Total Food Collected: " + foodCollected;
            foodOnStage.splice(i,1);
            if (foodCollected >=50)
            {
                basket_mc.gotoAndStop(50);
                gotoAndStop("win")
                field3_txt.text="You Won!";
            }
            else if (foodCollected > 45)
            {
                basket_mc.gotoAndStop(45);
            }
            else if (foodCollected > 40)
            {
                basket_mc.gotoAndStop(40);
            }
            else if (foodCollected > 35)
            {
                basket_mc.gotoAndStop(35);
            }
            else if (foodCollected > 30)
            {
                basket_mc.gotoAndStop(30);
            }
            else if (foodCollected > 25)
            {
                basket_mc.gotoAndStop(25);
            }
            else if (foodCollected > 20)
            {
                basket_mc.gotoAndStop(20);
            }
            else if (foodCollected > 15)
            {
                basket_mc.gotoAndStop(15);
            }
            else if (foodCollected >10)
            {
                basket_mc.gotoAndStop(10);
            }
            else if (foodCollected >5)
            {
                basket_mc.gotoAndStop(5);
            }
        }
    }
}