Hi,
Thank you for posting in Symantec community.
Need to check log.liveupdate logs.
Log.liveupdate could be found in -
Windows 2003: C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate
Windows 2008: C:\ProgramData\Symantec\LiveUpdate
Return code = 4 is very commonly seen however check the following article.
Do you see any error in the event viewer?
Error: LiveUpdate encountered one or more errors. Return code = 4" in LiveUpdate status in Symantec Endpoint Protection Manager. Try to run liveupdate manually you may face different error message.
To run it manually go to Start --> Run --> Luall.exe
http://www.symantec.com/docs/TECH103112
Best practice for configuring LiveUpdate when installing a Symantec Endpoint Protection Manager and Symantec Endpoint Protection client on the same machine.'
http://www.symantec.com/docs/TECH102337