Who's online, unknown location

[Lynne]

Can you please check your session table and see what location is listed and also see if they are listed as all having the same IP or different IPs.

You do have several modifications on there and you need to disable them to see if you still get this problem.
Note: To temporarily disable the plugin system, edit includes/config.php and add this line right under <?php

PHP Code:

define('DISABLE_HOOKS', true);