Maybe you should get the debugger version of the Flash Player so you can possibly see the source of the failure.
Where is the shell swf relative to the player swf? Could it be a pathing issue for a file it is trying to load?
I have the Debugger version. There is no official "failure", as in, no errors are actually thrown.
The shell, and the player SWF are in the same folder. All files are loaded properly. No 404, or security errors.
The video loads, plays, etc. Essentially, everything is running exactly the same as it does when it runs correctly. The only issue is visibility of that one asset in the player SWF, being the actual player. Other assets in the player SWF are visible.
You'll need to look thru the code of the player to see what might be putting it out of place when you change its environment to being a loaded file. Maybe it is present but ends up being somewhere off stage due to some settings. Try tracing its position after it is loaded to see where it is.