Event 1136 after Exchange 2013 Active Directory schema Preparation

I am in the process to migrate to Exchange 2013 from Exchange 2007.  The domain controller is on Windows Server 2003. I did the Exchange 2013 set up by using 'setup /PrepareAD' on Windows Server 2012 and it seemed okay.  However, I found the event ID 1136 (Active Directory failed to create an index for the following attribute.) on the attributes below

msExchArchiveRelease
msExchBypassAudit
msExchMailboxAuditEnable
msExchMailboxRelease
msExchPreviousRecipientTypeDetails
msExchRecipientSoftDeletedStatus
msExchResourceSearchProperties
msExchTransportRuleState
msExchUserHoldPolicies

Additional Data
Error value:
-1403 JET_errIndexDuplicate, Index is already defined.

How can I resolve/address the above errors?  Also can the installation on Exchange 2013 be continued?

Thanks

Lawrence