Long story short, we had to rebuild exchange 2010 in our lab. After running ADSI edit to remove the system mailboxs we tried to reinstall on new server and install the Mailbox Role. The error above is reference b/c we deleted an object in AD that we should not have. Tried running /preparead but we recieve the error Setup encountered a problem while validating the state of Active Directory. The Active Directory organization configuration version (12640) is higher than Setup's version(12639). Therefore, PrepareAD can't be executed. Anyone ever seen this before and know a work around?