Can't progress the Isle of the Gods

I get to the part where I am supposed to pop the darkspawn boils, but after doing so the Alpha Hurlock's keep spawning and I can't progress forward. The way forward is blocked by blight and after getting rid of all the boils, it still has not lit up - so I'm stuck fighting Alpha Hurlocks. 

And I can't save because any save that is NOT at the lighthouse does not load, meaning I would have to do the entire mission again. 

Anyone else experience this, and if so, have they figured out a solution?