1) Under what circumstances does this error message pop up? 2) I don't think so, but I could be wrong. No$GBA isn't exactly the epitome of complicated, though. In terms of GBA emulators, you should use VBA-M over anything else, but I haven't checked if it support solar sensor adjusting. In NDS terms, No$GBA is where it's at. 3) Try No Frills @ Pocket Heaven 4) Asking here or Googling 5) Master codes are codes that need to be enabled prior to enabling any other codes. 6) Depends on whether you want to group all your emulators and play each one just by using a single program (i.e. a frontend), or just play each emulator separately. Rather, define "flexible". 7) Only the gods of emulation know that, and only after you've asked enough questions to warrant a gag order.