During the setup of Office Communications Server 2007, the AD Prep Schema actions fails with the following error:
Failure [0x8007054B] The specified domain either does not exist or could not be contacted.
This is most likely caused by Active Directory connectivity problems. To find the source of the problem, verify the following AD settings:
DNS, verify that DNS is working for servernames and AD PTR/SRV records
Verify that Schema Master is online and can be contacted from the OCS server
Verify that Schema Master is writeable
Verify Domain Controller replication (DCdiag)
To work around this issue, try completing the task from another server, or Domain Controller