The salves you need to use to get through the barriers are not working. I drink the correct one (Nature's Balm), let the animation finish, get the buff then the moment I step inside the barrier, I take as much damage as normal and the salve buff just vanishes, Same thing with the Fireheart Salve on the frost one, and Coolmist Salve in the fire one.
I tried relogging, abandoning quest and restarting it, I even tried the other 2 salves even if they're not the correct one and same result each time.
I died a few times because it's a new character on a fresh account (no CP). But I still managed to do it . The only workaround I found was to simply run the whole way and drink a healing potion at the end so I don't die.