Don't know how to open up the gates but there is a cave to the south of the p*** that will
lead you to the other side. If you can't find the cave just wait until your main quests
lead you right to the cave.

Hope this helps

You will be unable to open the gate in any of the good aligned quests. The only time I
could open it was playing the inquisitor.

I am playing as the inquisitor and found the cave with the weird computer looking thing
and the blue turrets. I visited this cave and activated said computer, the cave rumbled,
and nothing else happened. Following this I returned to the gate and nothing happened AT
ALL!

i am playing as the inquisitor, and when i came to the gate i talked to one person then
clicked on the door and it just opened, no tricks, i just walked right through.
No matter what quest you are skip the main quest at this point and look up the quest for
getting your unique mount. once you are past dragonmaw p*** you take a different path from
the one you would take if you were doing the main quest.
it is so worth it.
you move way faster, and especially the inquisitor mount is freakin GANGSTA!!

well it realy doz matter if you are shadow or light. they take almost compleatley difrent
paths