What should my program output if every scout explored some part of the map (without any contradiction to himself), but there is no map that satisfies scout's "submaps" together?

You are not asked about "submaps", but instead whether it is possible to construct a map with two given routes. So, as you see, your question is completely rhetorical.

Ok.
1) There aro two routes.
2) It's impossible to determine coordinates of at least one scout.
3) It's possible to construct map with the first route (without the second).
4) It's possible to construct map with the second route (without the first).
5) It's impossible to construct map with both routes together.
What to output: "There is not enough data" or "A mistake has been made at step number X"?
And (if the second case) how to determine X? Take maximal X?