hey, i got the same problem buuut i solved it!
today (17:22 14/11/2012) i dc’ed 5 times in a row :/
and since that moment i couldnt log in anymore
i tried everything, and nothing did work but i solved it, i just logged into another pc and i didnt dc.
i thought it was my pc, but then again i tried to log in to my main pc and no problems at all.
im playing 30 minutes now and no dc.
so i think you can solve it to log in to another pc!
sorry for the bad english
GL