Thanks for the info.
I have found logs from both Hyperion and Arienna. They both show that they sent some bad packets, and therefore the characters are getting in that lockdown state. This makes sense, as you used both from the same computer. Since this has happened twice in a row for you, I would guess that something is messing with your computer (either a virus, or an anti-virus deleting files).
Until I tweak the security feature, I would suggest trying a different computer, running a virus scan (Microsoft Security Essentials is MS’s free AV), and finally trying a different network.
Server’s restarted, but please try my suggestions to avoid this.