Check to make sure that your throttle stick is all the way down and your trim for the throttle is also all the way down. Turn off the idle up switch and never touch that until your blades are spinning at full speed, usally in the air when you want to flip her upside down.
Sometimes my CP Pro (v1) wouldn't work either and I just had to wait a few more seconds or unplug it and do it again. I never could figure out why.
Blessings,

Jay