Can you close the door and open it again? Is something blocking your way to the door, or is there a problem with the door itself?

Try saving the game and re-loading. A couple people have run into a problem with a door in Elrath's cellar remaining blocked even after the crates in front of it were removed, but reloading would fix it.

Also;
Teleporting Anywhere, via hex editor

or use the following to temporairily get out long enough to pick up a teleporter stone
FIX for the Missing Catacombs Portal