so, i made a 30 second long matinee for like a game demonstration video. so now i want to export it as .avi. i click the “movie” button top right in the matenee to export it. i export it as 1280 X 720 30FPS .avi file. the file is saved, but whenever i try to play or use it, it says that 'This items file format may be unsuported, the file extension may be incorrect! please help me!