I was having problems arming my ArduCopter. This is how I was finally able to get them going.
It should be noted when arming the motors you have to press right on the rudder/throttle WAIT (About 2 seconds) and then throttle up a little past 50% and HOLD there for about 5 seconds. I also wait for the GPS to get a lock before I attempt to start.
My experience arming the motors by moving the throttle right then quickly to the 50%+ mark never started the motors.
Hope it help with anyone having difficulties.
I'm topping off the LIPO and next stop first flight.