Do you mean they are not playing, or not even showing up in the file browser? If the latter, check file extensions. The default emulator needs roms with the extension .smc. Roms with the extension .sfc can be changed with a converter, or you can play them with DingooSnes (look for DEP version 2.0) or the .app version of PocketSNES.
GBC,GBA,GBA SP,NDS,NGPC,Panasonic FZ-10 3DO,NES,Sega Nomad,Sega CDX w/Power Base Converter,PS1,PS2,PS3,Saturn,Dreamcast,PC (Win 98, XP, 7),Dingoo A320,Dingoo A330,Gemei A330,LetCool N350JP,PAP-GAMETA,GCW-Zero SE,Kyocera Rise,2DS,GP2X-F100,GPD G7,JXD 100,JXD A1000,JXD A3300,JXD F3000,JXD V5000,JXD S7300B,Hyperkin SupaBoy
Currently playing: Theatrhythm Final Fantasy Curtain Call (2DS)