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::DisplayObjectContainer/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.