It all seems to stem from the Ajax control throwing an encoder state error, what exactly that means I am not sure, it could be noise on the encoder lines giving bad feedback, could be the encoder is not being seen at all, could be just your tuning of the motors.
Really you need to talk to Ajax as the message re encoder is generated by their plugin so hopefully they can point you in the right direction.
I d seem to recall someone else with a similar message, from an Ajax setup, posted a year or so ago, cant remember what the outcome was but maybe a search of the forum would find something.
Hood