Hmm... did you check that the file referred (Audio/BGM/Rejuvenation - Title Screen.mp3) exists? I had a similar issue where some scripts where missing for some reason.
Is this the only error? As far as I know the missing sounds won't stop the game from working (I even tested removing the Audio directory).
I think you can comment out the part of the code that raises the error (Scripts/Game_System.rb) without issues (bar getting no bg music), but I doubt this will help:
def bgm_play_internal2(name,volume,pitch,position) # :nodoc:
#begin
# Audio.bgm_play(name,volume,pitch,position)
#rescue ArgumentError
# Audio.bgm_play(name,volume,pitch)
#end
end