loading youtube video

Hi

In  a video player built in as2. We are loading video's from youtube with following code. Some of the video files are not loading. Please give some idea what could be the problem as no error message is showing.

var mcl = new MovieClipLoader();

mcl.addListener(this);

mcl.loadClip("http://www.youtube.com/apiplayer?key=AI39si7R_f5iOwuEtaye838aWpZQ-xhCnlnkIq5QG997wXCigU84IVy9NalTBF-6P_FcEvkODHH-NQVRAXq68Bbjl4DUoVI7hg&v=ZeBd_F2Bz5Y", holder_mc);

Thanks--------Amit