Topic on Help talk:Extension:FileImporter

The license template needs to be listed as a "good" template.

Why the FileImporter do not allow me to import files with PD-RusEmpire license?

Because it's not listed in the "good templates" list in the FileImporter data page for your wiki. Assuming you are trying to import from the Ukranian Wikipedia, that would be Extension:FileImporter/Data/uk.wikipedia#Good

Ok, thank you. I will add this