We receive the following error from SCOM2007 R2 for our Exchange 2010 SP2 RU4v2 CAS. I don't see anything in the event logs. I ran across the below KB but it really doesn't apply to our environment as we have no Exchange 2003. We are still running a mixed 2007 environment though. However, that won't be for much longer.
http://support.microsoft.com/kb/2639150
Alert: Application Pool worker process is unresponsive
Source: MSExchangeSyncAppPool
Path: CAS04.dir.contoso.com
Last modified by: Auto-resolve
Last modified time: 2/3/2013 4:00:04 AM
Alert description: A process serving application pool 'MSExchangeSyncAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was '7384'. The data field contains the error number.
Alert Severity: 1
Alert Priority: 1