SEPM 11.x no longer updating

Hello,

my SEPM (11.0.6100.645) don't want to update anymore. I followed this guide to fix the problem: http://www.symantec.com/business/support/index?page=content&id=TECH104721 but it does not help. SEPM still shows latest Virus defs 2013-07-17 rev 022 (downloaded 2013-06-18 10:41:11 MESZ).

Any idea how I can fix it?

Kind regards,
Dennis