Symptom

During the process of a Full Import on the Active Directory Management Agent there is a reference on an Active Directory Organizational Unit to an Organizational Unit two levels down, the Synchronization Service Engine will crash.

Cause

A known issue in the Synchronization Service Engine.   

Resolution

Fixed in build 4.1.3479.0 

Additional Information

A hotfix rollup package (build 4.1.3479.0) is available for Forefront Identity Manager 2010 R2 

http://support.microsoft.com/kb/2889529 

 As of 10/30/2013, this fix is not yet ported to DirSync.