Hmm, since one of these videos plays but the other two do not, i think we can rule out SSL as culprit, since all URLs are HTTPS and look-alike. They played for me, so is not cookie/authorization thing either. They seem to all use the same video (h264) and audio codecs.
The difference i see is in the resolutions - 640x360 (works), 1280x720 and 1920x1080. So my next guess is perhaps googleUserContent.com does not provide enough bandwidth? Can you get any diagnostics from the player object/events?
Also, have you tried the same video files on another server, as a way to decide if it's the file format or the hosting?
