Check this post about multistep analyses in CalculiX: Understanding multistep analyses
PrePoMax propagates BCs and loads by default (uses OP=NEW and redefines these features) or they can be propagated manually if automatic propagation wasn’t applied (e.g. because of some changes in the step sequence).
The error simply means that you have two conflicting (due to different amplitudes) loads applied to the same node and degree of freedom.
If you want to modify the load in the second step, you can edit it there to change the magnitude or amplitude. If you want to keep it and add a new one, it should act on different nodes/DOF.