Arduino IDE Unable to detect ZumoMotor.H ( PIXY PET )
It looks like you need to install the ZumoMotors library.

There's one available at the following link, although I don't know for sure that it's the same one your Pixy Pet requires:


https://github.com/pololu/zumo-shield


That page includes instructions on how to install the libraries. If you get stuck, there's more help in the official Arduino documentation:


http://arduino.cc/en/Guide/Libraries