  We correct the error in the sign of the pseudoscalar pole contribution to the
muon g-2, which dominates the O(alpha^3) hadronic light-by-light scattering
effect. The error originates from our oversight of a feature of the algebraic
manipulation program FORM which defines the epsilon-tensor in such a way that
it satisfies the relation epsilon_{mu_1 mu_2 mu_3 mu_4} epsilon_{nu_1 nu_2 nu_3
nu_4} eta^{mu_1 nu_1} eta^{mu_2 nu_2} eta^{mu_3 nu_3} eta^{mu_4 nu_4} = 24,
irrespective of space-time metric. To circumvent this problem, we replaced the
product epsilon_{mu_1 mu_2 mu_3 mu_4} epsilon_{nu_1 nu_2 nu_3 nu_4} by -
eta_{mu_1 nu_1} eta_{mu_2 nu_2} eta_{mu_3 nu_3} eta_{mu_4 nu_4} \pm cdots in
the FORM-formatted program, and obtained a positive value for the pseudoscalar
pole contribution, in agreement with the recent result obtained by Knecht {\it
et al}.
