I don't know. I THOUGHT it was SC-3000. It's Drol. The rom ends in .sc. I got it from romhustler in the sega master system section.Are you sure that you are not loading a SC1000 game ?
http://romhustler.net/rom/sms/drol-sc-3000
I tried /sc, which was the default. It didn't work. I tried /sms. It didn't work. I even tried mame2003 and THAT didn't work.
I just found a rom that ends in .sg.....if you think that will help.