Video Streaming Issue with Rolling Audio

Question

I have several flash based lessons that I have created that are being distributed online to several companies.
Each lesson has a video that is played within the lesson through the flvplayback control. The videos were supplied by a third party and some of the videos are encoded at 384K and some are at 568K.
One company that is attempting to view the lessons is seeing the following behavior. The video plays for approximately 20 seconds then suddenly the video drops out and the audio continues to play. With the audio still playing the video scrubber rolls back and attempts to start the video again but all that comes through is the audio track again. Now there are 2 instances of the audio playing with no video. This happens a third time and finally keeps going until all the audio is played out.
The IT staff at the company has showed me a fiddler log that shows the flash player making a connection out to Akamai to retrieve the video and then rolling from port 80 to port 1935 and finally to port 443. This would explain the three audio tracks playing
I have read that the flash player will attempt to gather the stream from the stated rtmp location and then if it encounters an issue with a proxy or firewall it will attempt the other ports.
So I am not sure if there is anything I can do by design or programatically to alleviate this issue. It appears to me that the company attempting to view this video has some kind of bandwidth throttling program in place that is kicking off this behavior in the flash player.
Is it possible to prevent the flash player from making the three attempts? Would a sudden cut of bandwidth prompt the player to attempt to roll to another port if a network load balancing program suddenly kicked in? If it is bandwidth is that why the audio stream continues to play because there is enough bandwidth for the audio track to get through, but not the video?
I have attached a screen shot of the sniffer output so you can see the rolling ports thing.

Answer 1

As it turns out they do not allow traffic over the default rtmp ports. They do have a proxy server in place, but it does allow http tunneling. I had one of the users on their network hit the port testing page that adobe provides and hit laptop passed the test by allowing tunneling.
Incidentally it can be found here if you need it: http://kb2.adobe.com/cps/164/tn_16466.html
I created a flash movie that had the flvplayback component in it streaming from one of the flv files I have on Akamai and it worked for the end user.
This was a little depressing because I was hoping I could simply blame his network and walk away .
I then changed the component in my lesson to specifically use tunneling and this worked for the end user with the video issue, but then caused issues for all the other companies viewing the lessons.
I believe they are using FP version 9.0.124.0 at this particular company and not unlike most places I have dealt with they tell me it is impossible to upgrade to FP10.
So I think what is happening is the scorm communications and the web service communications and the video and the load balancing software and the client side proxy server are all coming together to cause the issue.
It seems to me that it isn't an issue I can solve via changing publish settings or programmatically although I have been looking at the proxyType property of the NCManager for the flvplayback control to see if setting the fallback to CONNECT might solve the issue.