There is a possible bug a few people have encountered in the PC version; sometimes when quick saving/loading indoors ladders can get removed or doorways sealed. If you notice this right away, then exiting the game, restarting and reloading the save should work normally, but if you don't notice and save again it gets written into the save file.
Missing ladders in dungeon...stuck inside!How close to the beginning are you? It may be easier to just start a new game and avoid over-writing saves or using the quicksave feature (at least until the next patch is release, though I wouldn't expect that much before the add-on is out (August/September), since the testing and release procedures will likely be combined).
