Error #2035 but only on MAC OS ??? why ?

I have an application that displays swf files when user selects them with a file browse dialog. here is the code:

             private function dispDialog():void
            {
                var file:File = File.desktopDirectory;
                file.addEventListener(Event.SELECT,onFileOpen);
                file.browse(new Array(new FileFilter('SWF','*.swf')));
            }

            private var _instPath:String;
           
            private function onFileOpen(e:Event):void
            {
                _instPath = e.target.nativePath;
                verifyAnimation(e.target.nativePath);
            }

            private function verifyAnimation(path:String):void
            {
                vswfl = new SWFLoader();
               
                vswfl.addEventListener(Event.COMPLETE,onvSWFComplete);
                vswfl.addEventListener(IOErrorEvent.IO_ERROR,onvSwfLoadError);
                vswfl.load(path);
            }

            private function onvSWFComplete(e:Event):void
            {
               // ok

            }

            private function onvSwfLoadError(e:IOErrorEvent):void
            {
                Alert.show('error10006: This is not a valid b2a file! '+e.text,'error!',4,this);
            }

So when the user opens the application on Windows or Linux, everything is great, but when user has MAC OS X, the code displays error10006: This is not a valid b2a file! Error #2035

i think the code means  URL Not Found or something like that, but WHY only on MAC OS? And how can I fix this???

Thanks for your help in advance

it should work