Ming - php sync problem?

Hi all. I have simple page that generates a simple flash with some random images, then publishes it - on the same page. If I do this, i regularly have several kinds of problems, one of them, an error message like: getimagesize(img/topmovie/toplogo.swf): failed to open stream: No such file or directory or the size getimagesize reports isn't the correct one. If I only _call_ the swf (no generation), the message isn't there and things look more normal. Is the swf generation an asynchronous process and do I have to wait until the movie->save(xxx) finishes? Thanks for suggestions John