I'm having the same issue. No problems (other than the mass of people) since launch. All the sudden this week, can't connect with the 90K error. Well, most of the time I can connect, I can take 10 steps, and then I lose the connection with the error. I'm hoping to God they fix it in the upcoming maintenance.

The only thing I am thinking that works...try playing at OFF PEAK times. I was able to log in at 1AM last night and run around and play just fine. I was like WTF...IT WORKS?! But now, this morning, I can't get in again. It might have something to do with congestion on the server again.