“You love him too, don't you?”

I can not make screen caps of The Bride in Black or The Yellow Rose with the VLC media player. These movies start out playing then start slowing down then the picture freezes and the sound keeps on going. Does anyone know why it`s doing that and how I can fix it. The movies play on window media player and Real player, but not VLN. I want to make caps, is there anyway to make them with window or real player?