Flex, FileReferences upload() error in firefox

Question

hi all. swf file in https zone, upload script in http zone. File upload fine in ie, and not work on firefox, opera.

this code:

request.url = this.main.serverHostUpload + "/upload_web.php";

request.method = URLRequestMethod.POST;
request.contentType = "multipart/form-data; boundary=" + UploadPostHelper.getBoundary();

request.data = new URLVariables();
request.data.dst_file = fileDstName;

request.requestHeaders.push( new URLRequestHeader( 'Cache-Control', 'no-cache' ) );

var fr:FileReference = this.main.photos[this.iLoadPh].fr;
fr.cancel();

fr.addEventListener(DataEvent.UPLOAD_COMPLETE_DATA,createOrderStep6Res);
fr.upload(request,"file");