My issues with replays I've made on maps, for footage, was trying to review them, after exporting the map again. Once the map is changed, any replays on previous versions will not work correctly, even if the changes are small. I imagine this is not your problem, but either way, that is my experience. For the best footage, I recommend
Janne's Cheat Mod, and use a real time screen video capture program, like fraps, or overwolf. Cheat Mod will let you set up some real specific shots, with specific units...ect, and allow you to remove the UI for the capture, without having to learn the NIS process.
And thanks for the contributor status'.