The Microsoft article lists some of the primary causes of the 0xC103FC93 error you should consider troubleshooting when encountering this error.
I think you should pay close attention to this potential cause:
"DNS is not configured properly in Exchange Server. DNS may not be pointing to a DNS server that has a record for the Windows 2000 Active Directory directory service."
There are a couple additional causes listed, but I would always attempt to rule out any network and DNS issues first.
Do you have comments on this Ask the Expert Q&A? Let us know.
More on troubleshooting Microsoft Exchange setup errors:
This was first published in August 2007