Users who receive this error message should download the gateway selector program and choose another realm server to connect to. This problem occurs when a server has not yet received the message that you have logged off and still believes you're online.
If you cannot create a character on your desired realm or cannot log onto the realm with an existing character, then download the Gateway Selector from our FTP to manually select the gateway you connect to when you log onto Battle.net.
PC: Download
MAC: Download
After running the Gateway Selector and choosing the Realm on which you wish to play, run Diablo II: Lord of Destruction, connect to Battle.net, and log in with your Realm character.