Hello, it didn't work with the ID, so I replaced it with the KEY :
$output = '<div style="width:425px" id="'.$id.'"><iframe src="http://www.slideshare.net/slideshow/embed_code/key/'.$id.'" width="'.$width.'" height="'.$height.'" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"></iframe></div>';