Download the CKEditor MediaEmbed plugin from http://www.fluidbyte.net/embed-youtube-vimeo-etc-into-ckeditor
Extract the contents into sites/all/libraries/ckeditor/plugins folder, so that the file sites/all/libraries/ckeditor/plugins/MediaEmbed/plugin.js is available (notice the case in the plugin name)
Extract this module into the sites/all/modules folder