YouTube videos not playing in chromeless player in Flash using Zend_GData_Youtube class in PHP to pass results to flash (Works fine on Mac Safari??)

Question

I have been noticing some strange (but consistent) behavior with the chromeless YouTube Player API. I have a Flash AS2 SWF that uses cueVideoById() to show the thumbnail images of videos which works great. When the thumb is clicked I call playVideo() to play the video.

For some videos this loads the video and when I look at the traffic using firebug in Firefox I can see that a get_video call is being made to www.youtube.com - for example - http://www.youtube.com/get_video?video_id=LYhrYHmUPn0&t=vjVQa1PpcFPiP... For some other videos though this never works and in firebug i do not see any call being made - there is no get_video request when I try to play the video. I have tested this on both Windows and Mac machines and here are some observations -

1. Safari 5.0 (7533.16) Running on Windows XP
   
   First - Tried to load the following video - video_id=ZaI2IlHwmgQ - A get_video_info request is made but the video never loads and does not play.
   
   Second - Tried to load the following video - video_id=LYhrYHmUPn0 - get_video_info request made AND videoplayback request made to v3.lscache7.c.youtube.com AND get_video request made to www.youtube.com AND 4x s requests made to s2.youtube.com and set_awsome request made to www.youtube.com
   

2. Mozilla Firefox running on Windows XP - tried to load the same videos with exactly the same results.

3. Safari on Mac loaded all videos without any problems, I did not find a video that would not play

4. Mozilla Firefox on mac had similar problems where some videos would load and others would not.
   
   

It appears that for those that do not load the get_video_info request is being made but the videoplayback and get_video requests do not get made.

Has anyone found a fix for this problem or know what might be causing it. thanks