I think I caught a bug that needs dev support to fix...
As I mentioned in toon's thread about the RS2 environment addon for heg, I deleted the original map.rwm after installing the addon. I tried a custom battle or two - everything ok, except that "potidaia's" coordinates correspond to a sea square (no big deal).
When I tried to start a new campaign, I got kicked out to the main menu
I deleted again the map.rwm, tried again a new campaign, failed.
I uninstalled/reinstalled heg, everything plays ok - I delete map.rwm (to test) and again kicked out to main menu
There appears to be some sort of "misalignment" between the map files that generate the map.rwm and the campaign descr_strat definition - something that is "masked" by the already existing map.rwm in the base map folder. So, maybe a dev can check this one out - until then I'm not deleting my map.rwm again