Have you not activated any of the other teleporter pads?
If you step on a teleporter pad, and have the corresponding teleporter scroll in your inventory, it will activate the teleporter pad and bring up the map. On the teleporter map there should be a blue flame next to each teleporter pad that has been activated. Clicking on this flame will teleport your character to that location.
If you have not activated any other teleporter pads, there are a couple ways you can get out of the council hall:
Teleporting Anywhere, via hex editorOR
FIX for the Missing Catacombs Portal - drop one teleporter stone on the ground, save, use this procedure to temporarily get out of the council hall to drop the other teleporter stone on the ground, save again and finish the procedure to return to the council hall (you can then leave using the teleporter stones)
AFAIK there shouldn't be any problems playing under Vista.