“Movie Maker Doesn’t Support the Selected File Type”

I've been using Movie Maker for a few weeks, I've done maybe a 4 or 5 videos for school work, but just a few days ago I tried to bring a video up so I could finish/render it, when all of a sudden it said "Movie Maker Doesn't Support the Selected File Type. I've used Movie Maker before with the same video file type ( DSCN, and .wlmp) and all of the files transferred onto my Laptop and I've had no problems at all. Basically, I can get the files (DSCN) into the Movie Maker and it'll accept them just fine, but for some reason it doesn't support it's own file (.wlmp). This just doesn't make sense to me at all. Any help is appreciated, I've gotta get a video out soon for an online course. Thanks for listening to my nonsense, haha.