MP4 Video playback problem - any idea how to make it work?

Mp4 video files are working when opened from local filesystem but now working when opened from the web

Here is example:

var video:Video = new Video();

addChild(video);

var nc:NetConnection = new NetConnection();

nc.connect(null);

var customClient:Object = new Object();

customClient.onMetaData = ns_onMetaData;

var ns:NetStream = new NetStream(nc);

ns.client = customClient;

ns.play("http://www.voyda.eu/projects/not_working2.mp4"); // here is actual a file so you can test it

ns.play(url);

video.attachNetStream(ns);

Using above code will result in not playing the video file. Interesting think is that the same video file is played well when opening from local filesystem. Just download the file, change ns.play param to "not_working2.mp4"

ns.play("not_working2.mp4");

and see if it's working.