  Interesting magnetic structure found experimentally in a series of manganites
RMnO$_3$, where R is a rare earth, was explained, ostensibly, by Kimura et al,
in terms of a classical Heisenberg model with an assumed set of exchange
parameters, nearest-neighbor and next-nearest-neighbor interactions, $J_n$.
They calculated a phase diagram as a function of these parameters for the
ground state, in which the important "up-up-down-down" or E-phase occurs for
finite ratios of the $J_n$. In this Comment we show that this state does not
occur for such ratios; the error is traced to an incorrect method for
minimizing the energy. The correct phase diagram is given. We also point out
that the finite temperature phase diagram presented there is incorrect.
