My son has been trying to figure out how to complete the Finala's Contempt side quest for days now but no matter what he tries he is unable to go through the opened secret door in south Greilyn to destroy the towers. The doorway is just black.

I have found one other mention of this issue here http://garage.gaspowered.com/?q=node/5527 but as the door is already open there seems to be no solution.

Is there a patch that fixes this issue? Is there something else he needs to do to go through the door? He has the required level characters. This is the last part of the game as he has completed everything else and is desperate for any ideas.

Any help greatly appreciated