Got the problem fixed. It was a bug and I found the answer on the
planetdungeonsiege forum.

"alienbelien" wrote:

> Where can I report bugs for Dungeon Siege 2?
>
> I might as well explain it:
> In the quest for the Dryad Exile colony I have to save the Old Man. When I
> reach him, he keeps telling to save/help him. He also keeps casting spells on
> himself. I have looked everywhere, but I cannot go further and I have
> dispatched all the enemies who've attacked him.
>
> It looks like that the program repeats the casting with the old man and has
> gotten stuck. This must be a bug.
>
> What to do now?