(a) Clerical mistakes. The Board may correct clerical mistakes while a case is pending, or within 60 days thereafter if a decision has not been appealed. If a Board decision is appealed, the Board may correct clerical mistakes only by leave of the appellate Court.

(b) Harmless error. The Board disregards errors that do not affect a substantive right of a party. No error in a ruling, order, or decision of the Board will be grounds for a new hearing or for vacating, reconsidering, modifying, or otherwise disturbing a decision or order unless refusing to correct the error will prejudice a party or work a substantial injustice.