MS Exchange 2007 part of SBS 2008 - fully/current patched
Original problem is trying to add a Receive Connector .. fails .. see MS KB 2457729
As recommended by MS, ran:
[PS] C:\Windows\system32>Setup.com /prepareschema
Welcome to Microsoft Exchange Server 2007 Unattended Setup
Preparing Exchange Setup
Exchange Server setup encountered an error.
Can't find any solution/KB/workaround for this error from /prepareschema ..