Check that your Dynamixel servomotor is correctly configured. Do not hesitate to re-flash it with the ROBOTIS Software Roboplus. After re-flash remember to re-configure it. If the issue is not solved, contact us for an advanced support.
The motor is probably not well mounted. Check that you correctly mounted the horns by respecting the mark.
Check your power supply and the system cabling (try with a different servomotor). You can also reset the servo. If nothing works, the best solution is to go through the Dynamixel servomotor checklist!
The 1.0 protocol is specific to the Dynamixel AX and MX series. Protocol 2.0 has been developed with the new X series and Dynamixel Pro. Protocol 2.0 control tables include PID controls for extremely precise adjustment of servo movements. The firmware of the MX series servos can be upgraded to use protocol 2.0. You can refer to the protocol 1.0 and protocol 2.0 pages for more information.