I was not able to install SEP MR5, SEP MR6A & SEP MR6 MP1.
Check the attach file & log for the same.
delete all symantec and liveupdate folders
install liveupdate first
then install symantec endpoint protection
Please don't forget to mark your thread solved with whatever answer helped you : ) Rafeeq
Make sure you update Windows installer. That fixes this problem everytime for me.