as per the logs :-
EVENT - SERVER SELECTION FAILED EVENT - LiveUpdate failed to connect to server liveupdate.symantecliveupdate.com at path via a HTTP connection. The server connection attempt failed with a return code of 1813, Proxy or host authorization is incorrect
11/25/2012, 20:19:02 GMT -> Progress Update: DOWNLOAD_FILE_START: URL: "http://liveupdate.symantecliveupdate.com/liveupdate_3.3.1.23_english_livetri.zip", Estimated Size: 0, Destination Folder: "C:\ProgramData\Symantec\LiveUpdate\Downloads"
11/25/2012, 20:19:02 GMT -> HttpSendRequest (status 403): Request failed - Look up status code for more information.
The request is not getting through from proxy using system profile.
Suggest to try following links
URL http://www.symantec.com/docs/TECH131478
Also add full access to system profile for liveupdate service.
Hope this resolves your issue.