I've killed Joril then I talked to Davin to free all the slaves, but what am I supposed to do after that to get to chapter 6? Nothing leads me to do anything else. What am I missing?

Nevermind I found it. DUH!!!

Well, you should probably kill all the ice salamanders, for a start. Also find Vera and talk to her.

And remember that rickety old bridge in the southwest corner? You have to cross that next. There's a book on engineering in the cellar -- over on the west side -- that will allow you to repair the bridge. Or if the slaves are still there, talk to Soth.

After you finish with the area across the bridge, go to the area where you exit to the travel map. There's a cave to the east that takes you to chapter 6.