Check the Logs directory on a client
For XP/2003 it would be C:\Documents and Settings\All Users\Application Data\Symantec\Symantec Endpoint Protection\{Client version}\Data\Logs
For Win7/2008 it would be C:\ProgramData\Symantec\Symantec Endpoint Protection\{Client version}\Data\Logs
They should have a .log extension and you can open in notepad. They will be readable.