Some modding problems

[Viking]

I was thinking of letting The Seleucid Empire start with a huge city, so that they had some advantages against Egypt.
So I tried this:

level huge_city
region Syria

year_founded 0
population 25000
settlement_tax 51
plan_set default_set
faction_creator macedon
building
{
type core_building royal_palace
}

But when I tried to start an Imperial Campaign with TSE, the game just went into the main menu.
I can`t see what I have done wrong, but then a clever member, Mikeus Caesar, said something about an error command that could tell me what was wrong.
How do I use it?

And can anyone by just looking at text above tell me what that I have done wrong?

Thanks, Viking