Try typing this into your ssh session:
mupen64plus --resolution 320x240 --fullscreen /home/cpi/games/mupen64/pokemon.n64(Rename your rom to something simple without spaces for now, otherwise you’ll need to type “Pokemon\ Stadium\ (USA)\ 1.12.n64” if it’s called “Pokemon Stadium (USA) 1.12.n64”)
It sounds like you ran the script to install the dependencies to completion. Did you try the rest of the script to modify the action.config and config file?
Also check this thread. This person had a similar problem.