You should be able to toss a teleporter stone through the barricade to get back in.
Are other quest opened locations in the Dark Forest re-sealed? (the second level of the dwarven mines, for example). It sounds like you may have had a problem with the world.x2 file and it got replaced. The world.x1 becoming corrupt is what causes problems entering Verdistis, and any missing world.* files are what causes the
black map bug (primarily just in the 1.33 patch under certain circumstances).
