Be aware that instructables are, by and large, crap. That links you posted will not work for me so I can’t make comments. However the really wording bit is the suggestion you are using Arduino’s output pins as power and ground.
Can you post a schematic of your circuit, not a Fritzing piece of crap but a schematic, pencil and paper is fine.
As a test change your loop function to send out a note, just like the standard blink program. Then we might be able to separate problems between your Arduino and the setup of Live.