  The second author formulated quantum unique ergodicity for Eisenstein series
in the prime level aspect in "Equidistribution of Eisenstein series in the
level aspect", Commun. Math. Phys. 289(3), 1131-1150 (2009). We point out
errors and correct the proofs with partially weakened claims. This article of
corrigendum and addendum comprises three sections. Section 1 is devoted to
making concise corrections to the claim and the proof of Theorems 1.2 and 1.3,
and Sect. 2 serves as a modification of the computation of the contribution
from Maass cusp forms. Other relatively marginal mathematical issues and
notational/typographical errors are listed afterwards in Sect. 3.
