Managed client (Server 2008 R2) does not update virus definition

Dear all,

we use Symantec EPP 12.1 for our small server farm with

1 SBS2011 (based on Server 2008 R2)

2 Windows server 2008 R2 (clients)

and pc-clients

All clients are being served with updates by Symantec EPM, all clients are up to date except for one of the Windows Server 2008 R2.

All elements of Symantec are up to date as well, except for virus definitions. I executed liveupdate several times manually. Symantec tells me system is up to date and save, but the virus definitions are not updated as on other clients.

What should I do? How can I update the virus definitions on that client?

Thanks in advance

egydd