I am indebted to Professor Pentti Jarvi of the University of Helsinki, Helsinki, Finland, for pointing out to me that my paper A Simple Proof of Rad6's Theorem (Proc. Amer. Math. Soc. 85 (1982), 673-674) is in error. Indeed, my procedure, if correct, would prove that a continuous real-valued function, harmonic where it is not zero, is everywhere harmonic; this is not the case, as the simple examplef(x, y) = I x shows. My error is in my failure to justify the interchange of summation and integration in the equation at the bottom of page 673; although u l y = 2, u l (e,), there seems to be no easy way to conclude that the integrals of the summands form a series which converges to the integral JIM u Az dx dy. Although the collection of functions {e,L} is bounded, the collection {fA(ej,)} in general is not, and thus no standard interchange theorem can be applied-even though the equation at the bottom of page 673 is true, as we know from (other proofs of) Rad6's theorem. I regret the error.