Hello,
Is the SEP client communicating to the SEPM server?
Is the SEPM updated with the definitions?
Is this happening only on 1 of your client machine or there are a number of client machines which are not updating?
In case the SEPM is not updated, try to update the SEPM 12.0 by following the article below:
How to update definitions for Symantec Endpoint Protection Manager (SEPM) using a .jdb file
http://www.symantec.com/docs/TECH102607
and
To update the SEP clients 12.0, please follow the article below:
How to update definitions for Symantec Endpoint Protection using the Intelligent Updater
http://www.symantec.com/docs/TECH102606
Using Intelligent Updater files to update client virus and security risk definitions
http://www.symantec.com/docs/HOWTO55187
Hope that helps!!