How can I ensure that my AIR application displays .flv content consistently?

I am developing an AIR desktop application using Flash CS5.5. When the user opens the application, a short 2 second 'Welcome' .flv plays within the .swf before the UI appears.

For some reason, this .flv video is not at all visible on some computers, but displays fine on others. For instance, I can see the video when I install and run the application on one PC, but not on another that runs an identical version of Windows 7; there's just a blank space where the .flv should be. (This also happens on computers running XP and Mac OSX.) Each computer that I have tested on has an up to date version of the AIR runtime.

Everything else about the application performs as expected and I am at a loss as to why or how to fix it.

Has anyone else encountered a problem like this? Is there a known AIR bug concerning .flv videos?

Any help would be greatly, greatly appreciated. Thanks.