I have not had time to get back to this.
In case you have not resolved your questions as yet:
The error message tells you all you need to know.
“Whether a map is an input or output (write) map is indicated in its
If you look at the top right of a map settings you will see two entries: INPUT and WRITE
INPUT means “input” and WRITE means “output”.
A map can only be one. Thus, in your case you need two “versions” of the map, one input, one output.
If you have the map as input, you can save it under a new name, then edit the map. Go to map settings and change the X from INPUT to WRITE. Now stow the “write map”.
You should be able to take it from there.
Almost forgot, PM (print mode) has no bearing on this at all.