Excel Solver - Variable bounds conflict in binary or alldifferent constraint (19).

This message appears if you have both a binary or alldifferent constraint on a decision variable and a <= or >= constraint on the same variable (that is inconsistent with the binary or alldifferent specification), or if the same decision variable appears in more than one alldifferent constraint.  Binary integer variables always have a lower bound of 0 and an upper bound of 1; variables in an alldifferent group always have a lower bound of 1 and an upper bound of N, where N is the number of variables in the group.  You should check that the binary or alldifferent constraint is correct, and ensure that alldifferent constraints apply to non-overlapping groups of variables.  If a <= or >= constraint causes the conflict, remove it if possible and try to solve again.