(I couldn't find any resolution to the on going problem with Multiplicity in the forum, so....)
I'm running Windows 7 (x64) on my home network. (5 desktop, 1 lap)
Norton Internet Security 2011
I Never had a problem with Multiplicity Pro UNTIL I upgraded the software. It got to the the point that the thought of shock therapy and a padded room,seemed like a good alternative!
But, I decided to go back to what worked instead,which was "version 1.21 and I haven't had a single problem since!