Somedays I can’t see the obvious. I got this error when trying to reboot my vCenter 4.1 Lab server and the ESX 4.1 host it is on. Due to a lack of Nics I went against my own best practice and put the vCenter’s nic on a distributed switch. By doing this, in the reboot, obviously vCenter could not boot because it had no network attached to the nic (to be more specific, the distributed switch did not restart because vCenter was not running), it reported an error about not being able to connect to LDAP.
[2011-02-08 13:11:32.972 02480 info 'App'] [LdapBackup] Making sure LDAP instance VMwareVCMSDS is running
[2011-02-08 13:11:32.972 02480 info 'App'] [LdapBackup] Attempting to start service ADAM_VMwareVCMSDS...
[2011-02-08 13:11:32.972 02480 info 'App'] [LdapBackup] Service stopped, starting
[2011-02-08 13:17:50.003 02480 error 'App'] [LdapBackup] Timed out waiting for service.
[2011-02-08 13:17:56.003 02480 error 'App'] [LDAP Client] Failed to connect to LDAP: 0x51 (Cannot contact the LDAP server.)
[2011-02-08 13:17:56.003 02480 error 'App'] [VpxdLdap] Failed to create LDAP client
because there was no network, the service could not start. The easiest solution was to add another nic to ESX, create a local vSwitch, tie to to that nic, then move the vCenter VM over to use it, then was able to power things back up properly.