Capcom vs Snk and Snk vs Capcom are different games. Snk vs Capcom: Chaos (made by SNK) is playable on mame but you can't play Capcom vs Snk or Capcom vs SNK 2 (made by Capcom) on mame since they are released on Sega's naomi arcade system which is not emulated yet. They are available for consoles ( Capcom vs Snk on playstation and dreamcast, dreamcast version is better and Capcom vs SNK 2 on dreamcast, PS2, xbox and gamecube) so you can play console versions with dreamcast and ps emulators.