The Director shall make findings of fact in such hearing, and the Director shall render his decision within 30 days after the termination of the hearing, unless additional time is required by him for a proper disposition of the matter. When the hearing has been conducted by a Hearing Officer, the Director shall review the findings of fact and recommendations of the Hearing Officer, and the transcribed record if a party has requested and paid for such record before rendering a decision. It shall be the duty of the Director to forward a copy of his decision by registered or certified mail, to the owner, operator, licensee or applicant within 5 days of rendition of such decision. Technical errors in the proceeding before the Director or Hearing Officer or their failure to observe the technical rules of evidence shall not be grounds for the reversal of any administrative decision unless it appears to the court that such error or failure materially affects the rights of any party and results in substantial injustice to him.