Super Mario Bros. NESticle troubles.

Okay, so I am having some trouble emulating any of the Super Mario Bros. Games on Nesticle. Ive tried them all, multiple times but they dont seem to work. I even tried downloading new Roms but that hasnt worked either. When i load them NESticle says ''Unable to open Rom'' in red letters at the bottom of the screen. I know the Roms work cause I have used them in NEStopia but I want to use them in NESticle. Im fairly sure that the formats of the Super Mario Roms are correct. Also, Final Fantasy works fine in NESticle, so i dont know what im doing wrong. Can anyone help please?