Why can’t I open a recorded .avi file in Windows Movie Maker?

I just recently began recording live gameplay footage on Battlefield 4 on my PC using the DxTory recording software. I have it correctly set to my monitor's native resolution, to record in .avi, and to my "video" folder. But, when I choose the video and "open with..." Windows Movie Maker, I get a 7 second file with a movie icon on the right of the display with yellow caution triangle in the middle, as if the file were corrupted. With that said, I can run the full recorded clip with Windows Media Player with no problem whatsoever. HELP WOULD BE MUCH APPRECIATED! :)