Harbor House Quest Bug?!

[flowsenN]

Hey guys,
I have a problem: In the quest where I swim with the dolphin to the harbour house, I can't open this damn door. According to the videos, it should open automatically, but nothing happens and the door remains locked.
I have already tried to load another savegame, but this was also unsuccessful.
Does anyone have any idea what the problem could be?

[flowsenN]

Any Ideas?