before I begin, just want to say Happy New Year 2014 to all..
Okay, I would like to share this screenshot below:
You have seen this error lately? must be panic right and start to search into the TechNet.
Here is the article link http://support.microsoft.com/kb/2734946 .
In my case, there is a some period that between domain controllers have not replicated. Some of the DC was offline when I installed Exchange Server. So the while setup the Exchange, the setup will extend the AD schema. So since the Schema partition is forestwide, it might change and update the Schema FSMO role as well.
Resolution: you can manually force replication or wait the replication time takes place.