Cannot install FFmpeg

When I select FFmpeg and hit the 'Install or Update' button, Mod Assistant claims that it is installed. However, when I launch Mod Assistant again, it will show FFmpeg as selected, but not installed (under the Installed column, there is only a - ).

I downloaded FFmpeg from BeatMods and copied the files into the Libs and Plugins folder and ran Mod Assistant again, but it still didn't show FFmpeg as being installed. I do not know if simply copying the FFmpeg files to those folders is enough or if anything else needs to be done.