I have used following code and worked fine for me ....and it will work when flash player 10 is installed and settings are changed as per below site:
FileRef.addEventListener(Event.SELECT,FileSelect);
FileRef.addEventListener(Event.COMPLETE,onFileComplete);
var filedata:ByteArray=new ByteArray();
public function onFileComplete(event : Event) : void
{
FileRef = event.currentTarget as FileReference;
filedata=FileRef.data;
var data:ByteArray = new ByteArray();
FileRef.data.readBytes(data,0,FileRef.data.length);
}
private function FileSelect(evt:Event):void
{
FileRef.load();
Txt_FileName.text=evt.currentTarget.name;
}
http://opensource.adobe.com/wiki/display/flexsdk/Targeting+Flash+Player+10[
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