Illarion.org

All my characters read playable and my sister tried logging in on her characters on another account, and the same message came up.

If you and your sister are using the same ip address (ie -> in the same house, on the same PC or in the same network) - then you've been 'caught' by the ip address tracker.

To solve this, pick a GM of your choice -

http://illarion.org/community/us_contact.php#4

Or send a PM to one of them, or talk to them over an instant messenger (or some even hang out in the IRC chat channel) - tell them your account name, your sister's account name - tell them that you have the same IP - and they should fix it in a jiffy

Thank you very much.