How do you go about adding to the song list? Whenever I start up it loads the mod just fine but when it start to load the sounds it says "song name" not loaded! (with song name being whatever I try to put in).

For some reason when I try to start factorio with this mod I keep getting this error:

Error while loading entity prototype "sniper-turret" (electric-turret):
Prototype "sniper-turret" registered twice
Modifications: Advanced-turrets