Asterix's Village?

[krasny]

Barabarians took a province of mine and settled.

Now I can't move troops onto the province or engage in diplomacy with them (eg. Declare war).

 

[RDG]

Barabarians took a province of mine and settled.

That would indeed be a nice event for the year 50 BC, according to Asterix's story.

Now I can't move troops onto the province or engage in diplomacy with them (eg. Declare war).

But of course this shouldn't happen...
I study the game for only some days now, so I can't exactly tell what to do. But in games like EU3 and HoI2 I would suggest to edit the save game, when knowing the province ID.