"MediaController" Component Acting Crazy!

Greetings…
Ok this has happened to me a couple times now, can anyone please help?!

I’ll drag an instance of the “MediaController” component and one of the “Media Display” component to the stage.

I’ll associate them using AS like so:
mediaDisplay_mc.associateController(mediaController_mc);

I’ll then load different FLV videos into the MediaDisplay component using setMedia();

It will work…sometimes.

Othertimes, I’ll make another FLA file, use the same technique and it wont work - the “MediaController” component will just sit there flickering back and forth between what looks like it’s horizontal and vertical states!

I dont get it…I can’t find anything different between the two FLA files?!

Can anyone help me with this?
Any help would be greatly appreciated.