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

**URL:** <https://forum.kirupa.com/t/typeerror-error-1009-cannot-access-a-property-or-method-of-a-null-object-reference/302914>\
**Category:** Uncategorized\
**Created:** [January 10, 2010, 1:38am UTC](https://forum.kirupa.com/t/typeerror-error-1009-cannot-access-a-property-or-method-of-a-null-object-reference/302914 "2010-01-10T01:38:13Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![butter](https://avatars.discourse-cdn.com/v4/letter/b/eb8c5e/32.png) [@butter](https://forum.kirupa.com/u/butter)\
**Post date:** [January 10, 2010, 1:38am UTC](https://forum.kirupa.com/t/typeerror-error-1009-cannot-access-a-property-or-method-of-a-null-object-reference/302914/1 "2010-01-10T01:38:13Z")

</div>

Hey guys I’m new to code, and here’s my problem. Any advice??

“TypeError: Error #1009: Cannot access a property or method of a null object reference.  
at type\_fla::whole\_1/thumbUp()”

Here’s my code

stop();

import caurina.transitions.\*;

var xOffset:Number;  
var xMin:Number = 0;  
var xMax:Number = sb.track.width - sb.thumb.width;

sb.thumb.addEventListener(MouseEvent.MOUSE\_DOWN, thumbDown);  
stage.addEventListener(MouseEvent.MOUSE\_UP, thumbUp);

function thumbDown(e:MouseEvent):void  
{  
stage.addEventListener(MouseEvent.MOUSE\_MOVE, thumbMove);  
xOffset = mouseX - sb.thumb.x;  
}

function thumbUp(e:MouseEvent):void  
{  
stage.removeEventListener(MouseEvent.MOUSE\_MOVE, thumbMove);  
}

function thumbMove(e:MouseEvent):void  
{  
sb.thumb.x = mouseX - xOffset;  
if(sb.thumb.x \<= xMin)  
sb.thumb.x = xMin;  
if(sb.thumb.x \>= xMax)  
sb.thumb.x = xMax;  
var sp:Number = sb.thumb.x / xMax;  
Tweener.addTween(content, {x:(-sp\*(content.width-masker.width)),  
time:1.5});  
e.updateAfterEvent();  
}