It's not the money, it's specific to Belgica. Anywhere I try to go around there it won't let me build anything, whether there are trees or not.

Another thing about Belgica is that everything moves slower there, even with paved roads. I think it's all swampland or something.

Funny thing though--The last battle I had in Belgica, there was a stone henge right on the beach! Why is it they can build a henge made of stone right on the beach in Belgica, but I can't build a wooden watchtower?