Lauszus:
@PeterCheng
You should not open the Graph code in the Arduino IDE, but in Processing: http://processing.org/.You can find more information in the readme: https://github.com/TKJElectronics/Example-Sketch-for-IMU-including-Kalman-filter/tree/master/IMU6DOF/MPU6050/Graph#developed-by-kristian-lauszus-tkj-electronics-2012.
It works perfectly thanks to ur help. And I'm also doing control motor DC (with encoder attached) by PID, so I'm looking for a program/graph apps which can show my signal response from my motor like the graph used for Mpu6050, can u suggest one ?