Does it instantly disconnect you after choosing which character you want to log in, does it disconnect during the loading screen, or does it disconnect at some other time?
If it is the first choice, did you recently change your video settings? I ask, because I was messing around with my settings last night, and had frequent "immediate disconnects upon character selection" issues.
sounds like you are caught in a death loop, Log onto an alt (or if you cant alt account) and file a petition for this, they will ask you for the toon's name and then waggle their fingers and perform some magics that will move you to a safe location or atleast be able to help you you can also try renaming (temporarily for testing purposes) your C:\Program Files\Funcom\Anarchy Online\Prefs folder to something else (when not running AO) and it will make a new pref's folder and see if that clears it up... if it dont then you can just remove the newly created pref's folder and rename the old one back to the proper name so all your packs etc are back as the were (as removing prefs will wipe out all custom names on packs and stuff thats why the renaming of the folder and not deletion of it)
also once a month you should run this command " /cc rembuddy ? " yes include the ? at the end this will clear out your 'recent messages' list of names as when this gets exceedingly large it causing stability issues.
