Amit, from the log it says
stopProtectedService: Unable to stop SmcService
then returns the error.
can you check from services.msc and see if all symantec services are started ( after rollback)
is it possible to remove the current version and install a fresh copy of 12.1.4?
do you have tamper protection enabled on this client, try disabling it once.
as far as I know, the current install seems to be corrupt, thats what I feel