It seems that either the definitions on the client are not updated or the installation is corrupt.

If the definitions are not updated you can update them using intelligent updater from the following link

http://www.symantec.com/avcenter/download/pages/US...

If the above does not work then repair the client.

If the steps provided my Warrior do not work then follow this

http://service1.symantec.com/SUPPORT/ent-security....

dcomcnfg.exe

Click OK.

Perform one of the following:

In Windows 2003/XP, expand Component Services, and then expand Computers. Right-click My Computer, and click Properties. On the Default Properties tab, on the Default Impersonation Level menu, click Identify.

In Windows 2000, on the Default Properties tab, on the Default Impersonation Level menu, click Identify.

Click OK.

Uninstall SEP

Change DCOM permissions

Re-install SEP

Incorrect DCOM Permissions prior to installation

To change the Default Impersonation Level using Dcomcnfg.exe

On the Windows taskbar, click Start > Run.

Type the following:

Hi,

The first easy step to do when you get this errro is to try to restart the Symantec Event Manager service, and answer Yes to the question about also restart Symantec Endpoint Protection service.