You need to tell us what version of flash each one of the browsers are using? Can IE be using a newer version or firefox. From my understanding flash is its own internal plugin for each browser.
Definately need more info to give a full answer.
<begin complete guess>
It looks like the IE flash player version is not high enough to properly play the flash file. It looks like it is loading the first frame (which has all of the assets laid out on it to aid with pre-loading). Then, the Actionscript that is supposed to play the movie fails because of the improper flash player version. So, the file stays at frame 1.
</end complete guess>
Your player detection/inclusion script should catch situations like this and provide alternate content to users without a high enough version of the Flash player. Use SWFObject for this. Be sure to set the SWFObject code to require the version of Flash that the file is published at.
It was due to bad embedding on my part, as 81bronco suggested. I started using SWFObject and all was well!