AIR error 2006 after loading <mx:HTML>

[kokababu]

I am new in AIR/Flex. I have created a browser using <mx:HTML>. During the loading, I am getting the following error:

RangeError: Error #2006: The supplied index is out of bounds.
at flash.display:isplayObjectContainer/getChildAt()
at mx.core::Container/getChildAt()
at mx.containers.utilityClasses::BoxLayout/updateDisplayList()
at mx.containers::Box/updateDisplayList()
at mx.core::UIComponent/validateDisplayList()
at mx.core::Container/validateDisplayList()
at mx.managers::LayoutManager/validateDisplayList()
at mx.managers::LayoutManager/doPhasedInstantiation()
at Function/http://adobe.com/AS3/2006/builtin::apply()
at mx.core::UIComponent/callLaterDispatcher2()
at mx.core::UIComponent/callLaterDispatcher()


I did not creating or adding or removing any child from my mxml file. My code snippet of mxml file is:

	
..........
			public function set jumpToUrl(value:String):void
			{
				_jumpToUrl = value;
				
				if (value != "" && value != null)
				{
					txtLocation.text = value;
					launchURL();
				}
			}

			private function launchURL():void
			{				
				htmlBrowser.location = txtLocation.text;		
			}

.........
.........
		<controls:TextInputOnScreen id="txtLocation"
				height="100%"
				styleName="urlBox"
				width="100%"
				click="_modifyLocation(event)"
				editable="false">

			<controls:filters>
				<mx:DropShadowFilter alpha="0.5"
									 inner="true" />
			</controls:filters>
<mx:HTML id="htmlBrowser"
			 height="{this.height - 50}"
			 width="{this.width}"
			 x="0"
			 y="50"/>

................

			 />

I would be glad if anyone help me about this issue.