Done it at last, Ignore the stupid green arrows pointing you to north gate, you need to go far north and wipe out a camp with scouts. Then it will be open.
I had the same problem, there were two enemies just inside the gate on the northern side. You can attack them through the wall. After killing them the gate on the southern side opened for me. Hope it helps.
lol glade I'm not the only one that this has happend to. Did what I was told and gate didn't open. So out of spit of the glitch I killed every thing on that map (zone) and then decided to go see if it was open and guess what it wasn't. lol after I did all that I read the quest log and serched for every name it said since it said koss had a deal with a boat. But I was wrong no mini boat to get me to that open door that you can't reach. Well thats my story on that quest I'll be trying again in a little bit.
yesterday we got it done, still don't know how it happened, we got owned by a mob, and then after rezzing in shrine gates were open, still we wandered around for a while before the mob thing
I have this quest active myself, but i havent looked to see if there was a certain hero requirement to get it to work yet or not. Several other quests and missions require a particular hero or another to have them work. Is this something that is being overlooked or undocumented? It simply wouldnt make sense to have a door trigger randomly between different groups of people. It would make some sense if it had something to do with varied party compositions though.