After an Auth Error I get a messagebox with the error "The password you specified is incorrect" and if I hit the OK-button, I stuck on another "Please wait ..."-messagebox saying "Authenticating". I have to kill the CentrED process with the taskmanager and restart the program.
Centred 0.6.1 Client on Windows XP SP3
I heard about such a behaviour before, but was never able to reproduce it. Therefore it's currently not really possible for me to fix it (since I have no idea what's the cause.)