This is typically a Timeout Issue:
To overcome this issue, change the timeout setting for LiveUpdate to extend the session period.
1. As per OS, browse to
Windows 2003: Default location is C:\Documents and Settings\All Users\Application Data\Symantec\Liveupdate
Windows 2008: Default location is C:\Programdata\Symantec\Liveupdate.
2. Open Settings.Liveupdate, find
PREFERENCES\INTERNET_CONNECT_TIMEOUT=45
PREFERENCES\INTERNET_READ_DATA_TIMEOUT=45
Change the default setting of 45 to a larger number, for example 600.
3. Save Settings.Liveupdate.
4. Run LiveUpdate to verify success.
It Must work..