dimitri wrote:
problem occurs when a character changes zones, not when logging in. source of solution provided: worked for another player with same issue. supporting information: op's client is more than a year old. post your version and perhaps nabutso can help you with the update process
Yes I'm aware its not just login but the point is that if you log in at the same time you can run into issues similar to this (the server/network getting confused as to who is who and sending the wrong packets to the wrong client).
Now, if this guy really is on a version that's that old OP might be missing the --hairpin flag in their launch options.
OP can either try first adding --hairpin to the launch options, if that doesn't work use the nasomi installer (you'll probably want to do this anyway). If you want, you can wait a little bit and nas will release a new and improved installer.