I have the same issue as state early, therfore its the issue of dulpicate hardware id in registery.
first stop SMC services than
Replace the sylink.xml file at below location.
c$\Documents and Settings\All Users\Application Data\Symantec\Symantec Endpoint Protection\12.1.1101.401.105\Data\Config
than delet the hardware id from below location
before that please stop tamper protection as showen below.
Hope this will help you