I don't like where this is headed!!!!!!
Mr Google pointed me to this KB regarding the above error: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1017577
Corrupt certificates? This is a little absurd. In the past I've upgraded from 5.1 to 5.1a then again to 5.1b no issues. AND I'm running vCenter in Linked mode and SSO in Multisite mode for SRM and vSphere Replication. Currently both vCenters "Prod and DR" running vSphere 5.1b are functioning fine, at least ALL services are running.