[flexcoders] Difficult to debug error.. Any ideas?

Hello, I have a viewstack with several children. Sometimes i get the following error when i switch views, but the problem is that sometimes it happens once every 4-5 switches sometimes the error goes away for several days... Any ideas on how to debug? TIA, Fotis TypeError: Error #1009:

Re: [flexcoders] Difficult to debug error.. Any ideas?

It seems that the problem is here: private function setPosFromValue():void { var n:int = _thumbCount; for (var i:int = 0; i n; i++) { var thumb:SliderThumb = SliderThumb(thumbs.getChildAt(i)); thumb.xPosition = getXFromValue(values[i]);