Hello everybody,

I have a strange problem when playing NEJ.
I've recovered the Heartstone Gem and return to the Archdruid. He gaves his speech about his enemies being defeated and teleporting away.
When I try to go upstairs in the house, the area won't load and I get a runtime error about 5 min later.

Any advice?

Check your installation.

Checked everything, Reinstalled according to your guide (Improved Anvil+TS+NEJ).
Started a new game, but now when I try to pick up Acalia, She turns hostile together with Hortgar when I leave the temple.

Any advice?

This is possible only if Hrothgar is not in your party, but then you wouldn't be able to advance so far.

My advice:

1. Clean install from scratch, i.e. SoA + ToB + ToB official patch + Baldurdash-WeiDU v1.64 + TS v6.11 + NeJ2 v6.9.1 + NeJ2 patch v6.9.3.
2. Start a new game.

[EDIT] Backup your OVERRIDE and DIALOG.TLK after installing Baldurdash to avoid further reinstalls.