Cal/Mail sync failing with "ADAM instance connect parameters is empty" and "Not Defined" (4286506)

The Calendar Agent log states "ADAM instance connect parameters is empty" when initializing, and then "redirector state:  'Not defined'" for every mailbox.  No synchronization is performed - the agent just cycles through mailboxes as follows:

6/21/2010 6:24:01 AM CADQueue::NextItem Informational 4511 Starting to process item '/O=OrgName/OU=Admingroup/cn=Recipients/cn=user1' (Collection 'Resource Mailboxes', PST: '61A402939ECBEC4BBBFF53401C2F51E7161', SyncMailboxInfo: 'True', SyncSwitched: 'False', SyncAllContent: 'False', SyncFolderContent: 'False').
6/21/2010 6:24:01 AM CMBRedir::MBRedir TraceMsg 1628438538      Starting LDAP asynchronous page search: DN = DC=corp,DC=absc,DC=local
6/21/2010 6:24:01 AM CMBMSwitcher::IsSwitched2 TraceMsg 4908 Current mailbox '/O=OrgName/OU=Admingroup/cn=Recipients/cn=user1' redirector state:  'Not defined'.
6/21/2010 6:24:01 AM CADQueue::NextItem Informational 4511 Starting to process item '/O=OrgName/OU=Admingroup/cn=Recipients/cn=user2' (Collection 'Resource Mailboxes', PST: 'B1EBE995CFEAFC4B96C6541B8CE9F246161', SyncMailboxInfo: 'True', SyncSwitched: 'False', SyncAllContent: 'False', SyncFolderContent: 'False').
6/21/2010 6:24:01 AM CMBRedir::MBRedir TraceMsg 1628438538      Starting LDAP asynchronous page search: DN = DC=corp,DC=absc,DC=local
6/21/2010 6:24:02 AM CMBMSwitcher::IsSwitched2 TraceMsg 4908 Current mailbox '/O=OrgName/OU=Admingroup/cn=Recipients/cn=user2' redirector state:  'Not defined'.
6/21/2010 6:24:02 AM CADQueue::NextItem Informational 4511 Starting to process item '/O=OrgName/OU=Admingroup/cn=Recipients/cn=user3' (Collection 'Resource Mailboxes', PST: 'C95118858B5E9246B72B29DB73CBB9CE161', SyncMailboxInfo: 'True', SyncSwitched: 'False', SyncAllContent: 'False', SyncFolderContent: 'False').
6/21/2010 6:24:02 AM CMBRedir::MBRedir TraceMsg 1628438538      Starting LDAP asynchronous page search: DN = DC=corp,DC=absc,DC=local
6/21/2010 6:24:02 AM CMBMS