I can't move at all so it can't be a texture error, anyone have any ideas?
Where your character is able to run is determined by the terrain you have loaded client side, so your Port Jeuno files probably just aren't loading properly for some reason. Maybe they're corrupted? Try reinstalling.
I remember a long time ago I occasionally had a glitch where pieces of land and objects from the wrong zones would randomly appear and I was able to run on top of them like they were normal. It was actually pretty neat, I could use it to go over the zone's normal obstacles and nobody else could tell. :D