While it has only recently occurred to me for the first time, apparently it's not all that uncommon for people to, upon entering The Gobsquat, to immediately warp onto the unreachable walls on the opposite side of the map.
This happened to me too. I assume it's lag, and nothing we can fix, but who knows? Any ideas?
If it's just a tileset issue, maybe a trigger placed on the wall in question, that sends the PC back to the spot near the entrance where they should be. Failing that, a placeable or one way transit, would be a easy enough short term solution until a permanent fix can be found.
A quick tip for getting stuck on walls when no DM is on...
If you are in an area where you can make a fire, use oil at your feet, and the fire will usually displace you down onto the ground again. I carry oil on some characters for this reason alone!
This happens sometimes. Each time it's happened to me (not so far on EfU: A, but on EfU several times)... the solution seems to be to just log off and then back on. You'll be back on the ground. Not sure what causes it, but I've had it happen in single player games as well!