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?