Are you trying to create the movies, or do you already have the movies created, and are trying to get it working in Mamewah.
You may want to stick with this threa
here if you are having difficulties creating your own. It looks like a pretty involved process.
Once you have the movies, here is how to get them working in Mamewah. I will be adding this shortly to the
Mamewah wiki.
First, make sure that you have added the movie_preview_path in your emulator .ini file with the directory to the previews. It should look something like:
movie_preview_path C:\mame\movies
Also in the .ini you need to specify a movie_artwork_no. This is the artwork number in the layout where the movie will play. Make sure that the artwork number you specify is visible in your layout, or you won't see the movie.