It isn't so. Hell, I killed them with a solo bard:

Save, then wait till golems separate. Have your thief/bard backstab him (with the Dagger of Venom, if you can afford it), than back off. If the poison damage doesn't kill him (and it does more often than not), either do it again, or trample him (it?) with your warriors and archers.

For Thalantyr himself, I wouldn't know. The only occasion when I killed him was with the same dagger. He doesn't survive such a thing.

Well now back to the actual subject;
I uninstalled everything, deleted all the leftover files, reinstalled and began a new game. When trying to get to the hills before Nashkel, the message popped up after shutting the game down while loading.

------------------------------------------------------------
| Microsoft Visual C++ Runtime Library |
|-----------------------------------------------------------
| |
| Runtime Error |
| |
| Program: C:\Program Files\Black Isle\Baldur's Gate\ |
| BGMAIN.EXE |
| |
| Abnormal Program Termination |
-------------------------------------------------------------
The Microsoft Visual is in the blue/Gray box and besides Runtime error is a yellow circle with a red X.

You should start a new game and try going to the same area. Maybe only your savegame is corrupted.

You could also go to Microsoft.com and download microsoft visual c++ runtime library.

What is your OS and direct X version?

Well like I stated in my last post, I uninstalled everything and deleted all the saves and other leftover files. I am not sure about Directx, but the OS is windows 98. But I don't think DirectX has to do with it as I also have SoA installed on the computer as well, and it works fine.

SoA is recent, while Bg1 is old. I heard of some problem when using Direct X 9.

It's not important if you re-installed the game, as far as I remember, the areas are saved in your savegame too.

Also, did you install the official patch?

can't find it. Can you tell me where it is?