Object Class Violation error via sync ADLDS with ADDS

Hi

I used to be able to sync my ADLDS instance with 2008 ADDS.  After I upgrade to 2008 R2 ADDS, I can no longer sync. and received error "An ldap error occured while saving the configuration file: Object Class Violation".

How do I upgrade my ADLDS instance schema to 2008 R2 so that I can snyc between ADLDS instance with 2008 R2 ADDS?