who mentioned me?

anyway I think that one might be straightforward

hopefully it is just telling you you have a faction listed in descr_regions.txt as the default faction for one of the regions (it's the third line down in each region entry) and that that faction isn't in the descr_strat.txt file for that campaign.

Most numbering in RTW starts from 0. It's probably either the 1st region you've got listed in descr_regions.txt file or possibly the one in the top left corner of the map (region ID numbering starts from there - but I wouldn't bet on that being the same thing)

generally anyway you shouldn't have factions used in the regions file that aren't in strat, if it makes a map.rwm at all you're likely to get crash later....

And welcome to the forum :)