I was in Chpt 2 right after witnessing Xzar being "silently killed" by a certain "supposedly Montaron" harper, Jaheira was approached by a sister harper and left my party for a while.About a day later she's back claiming that my party is being summoned to the Harpers' Hold in Athlaka.When we reached there, the door's locked!! I'm now in Chpt 3, Jaheira still insist me to report to the harpers' base and the the bloody door is still LOCKED!!!...................help.

i think you have to rescue the guy from the bandits first before you can get into the harper hold..
just trael back and forth in the city untill it says "you have been laid way by enemies and must defend youself" if you already did this and never picked up the body from the ground then i dunno if you can get into the harper hold.. dont take my word on that for sure though cuz i really dont know.