Can't get to play NeoGeo ISOs on Nebula

Hi there, new user here.

I have this problem about Nebula. When i try to play arcade ROMs i get no problem at all (though it was quite a burden to find all the required configuration files on the internet...), but when i load an ISO file (through a CUE file i had to create for each of my games), the NeoGeo starting splash and menu shows up, with all the options to play MP3s, the Memory and Start buttons and stuff. But i can't get to realy start any game: the Start button does nothing, the Memory one isn't related at all and not even the audio commands detect any track.

What is it i am doing wrong about? How to get things fixed?

Thanks guys, i can post any other info you need.