I had the same error 8504,104; and also 3052,2 with Norton v5.1.0.29 on Vista Business (Netherlands version) around January 31, 2012..
I found, or better say, happened to come to a solution without going back to factory settings. See below.
I contacted Norton Support and chatted with two case managers/supervisors.
Their solutions (Remove and Reinstall Norton 360, also in safe mode with networking; remove conflicting antivirus software) didn't help.
Norton 360 works fine after the reinstall, but once the LiveUpdate is performed manually and the PC is restarted as required, the error shows up in a window and this window with the error cannot be closed.
One supervisor asked for help from an engineer of the Symantect Engineering Support Team. This engineer called back to me and removed all kinds of traces of remnants of antivirus software (McAfee, Norton, Symantec, Avg, Webroot) and Malwarebytes-Antimalware software, also in the registry. All to no avail. So the engineer said that he would look up the error and call back the next day.
After this conversation I needed a working version of Norton 360.
As a workaround, I tried to remove and reinstall Norton 360 with the tool NRnR.exe and to avoid performing a manual LiveUpdate.
First, this remove and reinstall of Norton 360 led to a hang up of the removal process when it tried to save the user settings. Also in safe mode.
Therefore I downloaded the Norton Removal tool.
This tool was then used to remove the English version of Norton 360.
After the removal, Norton provided a link to download Norton 360. This appeared to be Netherlands version of Norton 360.
I installed this version and didn't perform a LiveUpdate.
The same Symantec engineer called back again (on February 6). He hasn't told me what the errors mean. Instead, he wanted that I again did a manual LiveUpdate. However, I insisted that the anti-tamper protection was temporarily unchecked and that as much as possible LiveUpdates would be performed before doing the restart. In this way I got a working Norton 360, even after doing several manual LiveUpdates
The Symantec engineer suggested that the Netherlands version may not have this issue. On the other hand , unchecking the anti-tamper protection and repeatedly performing manual LiveUpdates before doing a restart may also be the solution.
This had worked for at least one day. The errors haven't shown up again (I keep my fingers crossed after every LiveUpdate).