Here's a quote from Eric Isaacson over at BladeForums:
Okay, I logged out to see if I could login under someone elses login and now I can't get back in.
We definitely have a problem, I'm going to need to get assistance with this because I can't fix it on my end.
Luckily we still have BF.
Thanks for your patience
Eric
It sounds to me as if there may be a login Cookie issue, so if you haven't explicitly logged out of Rat Chat, you probably shouldn't until this issue is resolved.