Try the following steps
1. Delete the content of folder "C:\Documents and Settings\All users\Application Data\Symantec\LiveUpdate\Downloads\"
Note: Application Data is a hidden folder. Delete the content of the Downloads folder, but not the folder itself.
2. Update the LiveUpdate catalog by opening the following link in Internet Explorer:
http://localhost:9090/servlet/ConsoleServlet?ActionType=ConfigServer&action=PublishLuInventory
After few seconds you will get a confirmation message "Responsecode="0".
3. Stop the services "Symantec Endpoint Protection Manager" and "Symantec Endpoint Protection"
To stop the services:
Go to Start > Run.
Type the following: Services.msc
Select and stop the above mentioned services.
4. Delete the numbered or TMP folders inside the paths:
%programfiles%\symantec\symantec endpoint protection manager\inetpub\content\{1CD85...
%programfiles%\symantec\symantec endpoint protection manager\inetpub\content\{C60DC...
%programfiles%\common files\Symantec Shared\SymcData\sesmvirdef32
%programfiles%\common files\Symantec Shared\SymcData\sesmvirdef64
%programfiles%\common files\Symantec Shared\VirusDefs
6. Run Liveupdate from the Symantec Endpoint Protection Manager
Admin > Server > Local Site > Download Liveupdate Content
If this does not help
Title :'Update definitions for Symantec Endpoint Protection Manager using a JDB file'
Web Link:
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007100820002048