Don't work for me. In my data folder I've "paulscode.android.mupen64plus". I've try also with this command line: "exe=paulscode.android.mupen64plus/paulscode.android.mupen64plus.MainActivity" but no results, emulator won't launch.
***Edit***
With this it's ok now:
exe=paulscode.android.mupen64plus/paulscode.android.mupen64plusae.MainActivity
Parameters=