MPU-6050 Unsupported software product rev 4

Hello,
I started using the MotionDriver 5.1 today on a MPU-6050. The problem is that the mpu_init function terminates with the error 'Unsupported Software product rev 4'.
When trying to bypass this check, the next time I run the program I get a different error : 'Product ID read as 0 indicates device is either incompatible or an MPU3050'.

Does anybody have an idea what could be the root cause ?

Thanks
Henry