Erratum and Addendum to: Invariant Differential Operators and Eigenspace Representations on an Affine Symmetric Space

The purpose of this erratum and addendum is to correct the errors in [1]. It consists of five components: 1. Lemma 7.1 and Proposition 7.2 are wrong and discarded; 2. A new proof of existence $\lambda(\xi)$ in (7.1) without Proposition 7.2; 3. Definition of a new bijection in Theorem 5.2 and a proof by a new technique; 4. A new proof of Theorem 5.5 based on the new bijection in Theorem 5.2; 5. Correction to the list of exceptional simple pairs in Proposition 3.1. The main results of [1] remain true as stated. We also add a final remark on generalization.