Kirby superstar: key problems

When I turned on the ROM file "Kirby super star." a green message comes up and says the following: ------ (Please note) ----- If you are using the mouse, Super Scope or multiplayer adapter, switch to controller. From this notice I can't continue into the game and my keys don't work, they however work on other ROMs. Is it some sort of controller problem? Or is it some configuration I have to do? P.S. I'm using Znes emulator. "When i pass an automatic door and it opens i go inside anyway 'cause I might hurt it's feelings..."