He also raised the comment about "idiots" in her response to the key skills questions.
Ms Henderson said she filled in the form late at night and didn't intend on that line being included in the final copy.
The performance appraisal resulted in Ms Henderson being subject to a review, known as a 360 degree feedback review.
Ms Henderson said Mr Fleming told her the review would be when "all the demons came out". Mr Fleming told the ERA that he only referred to the "possibility of demons coming out".
A coach was brought in to train Ms Henderson to change her interpersonal style.
Ms Henderson took time off work and her GP deemed her unfit to return to work because of workplace stress. She then sent a letter to Mr Fleming claiming constructive dismissal.
Member of the authority David Appleton said Ms Henderson had been unfairly disadvantaged by the 360 degree feedback review.
"Ms Henderson was faced with the prospect of up to 80 people giving anonymous feedback about her, knowing that Mr Fleming believed that she was a poor performer in respect of her interpersonal relationships. No fair and reasonable employer could have gone down such a route in all the circumstances," he said in his decision.
Mr Fleming had confused elements of a performance appraisal with elements of a disciplinary process in his dealings with Ms Henderson, Mr Appleton said.
A constructive dismissal had not taken place, Mr Appleton said.
Ms Henderson had suffered a "palpable sense of humiliation" and loss of dignity, Mr Appleton said, and ordered the DHB to pay her $15,000 as reparation.