Your playing the 2 player version right? I found that out early on, what you need is the 4 player version. You can either unzip the 4 player version and take the needed files from there or you can just put both versions in the roms folder in which case the needed files will be found and both versions will work. You can also try the SNES version.
I also used the word version 7 times in this reply! :lol: