Error 8504 & 104

Hello

I am running Norton Security Suite ver. 5 and have been getting this error.  The first time I received it was after running virus scan when Norton blocked from two phising web sites.  I was on Google, must have hit  a link and Norton kept me from getting two different trojan from one site..  I ran a virus scan which came up clean and then a Malware scan which also came up clean.  However, when I went to scan again, I received this error.  I followed the instructions and ran liveupdate and rebooted and everthing was fine.  However, the next day, I ran another scan and received the same error, and since it said it was internal error, I removed and reinstalled Norton's.  Today, the same thing happened again.  I set it up to run a scan with live update first.  The scan came up clean but Live update said I had to reboot to receive the updates.  When I tried to close out the screen, I received these two errors.  I rebooted and did not receive it again.

 

My question is should I run the Power Eraser since the problems keeps happening or is it something with Live Update?  I worried that it keeps happening even though both Norton and Malbytes say my system is clean. 

 

Thank you