Did it display them for you prior to installing that program?
Have you got a HQ export of that segment that you can just re-import and use? So it's footage not a image file any more.
What's the error it gives you?
You know I cant really remember if I ever used .gif in wmm x_x I never had a problem with jpeg and png but I wasn't big into storing .gif on my computer sooo, I'm not sure if they should work of not *sigh*
new banzors in the making :p