Did you talk to Zixzax again and get the teleporter pyramid? Do you get a message when you click on the exit waypoint in the observatory? Can you use the waypoint in the main section to go to the hall of heroes and back?
Are you dragging around a dead party member, in need of resurrecting?
Me and my friend just encountered this problem as well.
and here is the answers to your questions.
"Did you talk to Zixzax again and get the teleporter pyramid"
- No. When we talk to him again he just gives us the same talk and options as in the main chamber before going to the observatory.
"Do you get a message when you click on the exit waypoint in the observatory?"
- No. we are unable to interact with the waypoint.
"Can you use the waypoint in the main section to go to the hall of heroes and back?"
- Yes. That works just fine.
"Are you dragging around a dead party member, in need of resurrecting?"
- no. all party members are alive.
Edit:
Problem was that we didnt click on any of the way point portals before going to the Shelter Plane which meant that we couldnt use the portal to get out lol... so we had to load it up before hand... I personally think that this should be raised as a bug as I didnt realise that you had to click on them or get stuck in limbo FOREVER! lol
Stelly
We used waypoint portals before going to the shelter plane.
