Hi,
Check log.liveupdate
Log.liveupdate could be found in -
Windows 2003: C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate
Windows 2008: C:\ProgramData\Symantec\LiveUpdate
How to Uninstall and Reinstall LiveUpdate When a Symantec Endpoint Protection Manager or Symantec Endpoint Protection Client is Installed (SEP 11.x)
http://www.symantec.com/docs/TECH102609
Download liveupdate setup at following location:
ftp://ftp.symantec.com/public/english_us_canada/liveupdate/3.3.0/