We've found that the update released by Microsoft today (October 13, 2009) to fix CryptoAPI issues will cause OCS services to fail.
The server will log event ID 12290 which says:
"The evaulation period for Microsoft Office Communications Server 2007 R2 has expired. Please upgrade from the evaluation version to the full released version of the product."
The server will then log event ID 12299 with the error code:
The KB article can be found at: http://support.microsoft.com/kb/974571
UPDATE (October 26, 2009) a new update has been released which resolves this issue. It can be found at: http://support.microsoft.com/kb/974571