This is extremely unlikely to be anything to do with either patch, once your connected, your connected, there is clearly some problem with your setup, have you tryed removing Winmx and doing a fresh install? Also your not using Zone Alarm by chance are you? Have you tried going back to 3.31 or even tried 3.54? Are you running any addons for MX? If so try removing them and see if that solves it....
Post back and let us know how you get on, also please post as many details about what your running as poss.