Are you sure you ran the Live Updater now ? There's nothing that we have changed in the FSX version of the software, is still using the same VC++ libraries and the same Simconnect version it always used on FSX.
So, either your antivirus is blocking, or something happened to your VC++ libraries.
I just tried it again now, just to be sure, and it works normally with FSX:SE here. Try the suggestions posted here:
http://www.fsdreamteam.com/forum/index.php/topic,14319.msg105559.html#msg105559Assuming it's not the antivirus, that utility should tell you which files are missing in your system.