You should try initialising the player in the onLoadContent event handler of TinyMCE.
E.g.
tinyMCE.init({
...
setup : function(ed) {
ed.onLoadContent.add(function(ed, o) {
jwplayer(id).setup({
file: video.href,
image: video.img,
title: video.title,
width: '640',
height: '360',
primary: 'flash',
aspectratio: '16:9'
});
});
}
});
The pont is that you need an element in user provided content to be available for DOM manipulation before setting up the player.