My friend and I have encountered this bug repeatedly. The 'reloadand try something different to no avail' is REAL. We cannot advance the story at this point since there is no way to save the game at the end of an evening's play. We have gone back to before the bug several times but it keeps recurring - even if neither of us listen in. The spot we are at is a certain zhent 1/2ling trader... which is as much as i can say without spoiling.
