# Parameter child must be non-null

**URL:** <https://forum.kirupa.com/t/parameter-child-must-be-non-null/319270>\
**Category:** Uncategorized\
**Created:** [February 15, 2011, 3:57am UTC](https://forum.kirupa.com/t/parameter-child-must-be-non-null/319270 "2011-02-15T03:57:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![pandu\_kirupa](https://avatars.discourse-cdn.com/v4/letter/p/cab0a1/32.png) [@pandu\_kirupa](https://forum.kirupa.com/u/pandu_kirupa)\
**Post date:** [February 15, 2011, 3:57am UTC](https://forum.kirupa.com/t/parameter-child-must-be-non-null/319270/1 "2011-02-15T03:57:20Z")

</div>

Hi all,

I am getting this error, whenever i loaded an external SWF file. I had an Interface, in which a glossary icon is set. So, when clicked, the glossary swf file has to be loaded in to Interface. So, I made a loader and added to display hierarchy, but left empty. So, when glossary icon is clicked, i am loading this specific glossary SWF file in to that loader. But, as it is added, the following Error is thrown.

```php

TypeError: Error #2007: Parameter child must be non-null.
    at flash.display::DisplayObjectContainer/addChildAt()
    at fl.controls::BaseButton/drawBackground()
    at fl.controls::LabelButton/draw()
    at fl.core::UIComponent/drawNow()
    at fl.controls::List/drawList()
    at fl.controls::List/draw()
    at fl.core::UIComponent/callLaterDispatcher()

```

I also tried to listen to Event.ADDED\_TO\_STAGE event before executing scripts in constructor of glossary SWF file. But still no luck.

By the way, the glossary SWF is loading just fine, but with this error being thrown.

Can any one please help in this regard.

Thanks  
Sateesh.J