I don't know if it's just superstition

, but I'm following a procedure that has prevented me from having this error so far since I started doing it.
It's as simple as re-loging in before closing eq after exiting a server. So, you want to stop playing: /camp and exit the server. Then it kicks you to the login screen (or at least it kicks me), so just log in back to the server selection screen, and then hit exit again and close EQ in a friendly way.
Hope it helps someone else

.