Did you replace the brushes?
The Following Error alarm happens when the ballscrew does not move as fast as the controller is expecting it to move. The way I understand it is that the controller supplies a certain voltage to the motor so it 'knows' how fast the screw should be rotating. If it does not detect an encoder count that matches the expected speed, within limits, then it alarms out with the following error.
If the brushes are badly worn, or sticking in their holders, they may not be making good contact so the motor may be running slow.