Question : Win2008 Domain Controller is rejecting replication requests

Our virtual machine Windows 2008 Standard Domain Controller running Exchange 2010 Standard is rejecting replication requests.

Reverting the virtual machine 10 minutes back in time was the cause of this problem.

Doen anyone know a method to get the Domain Controller accepting replication requests again?

Answer : Win2008 Domain Controller is rejecting replication requests

You're suffering from an USN Rollback. Snapshots may NOT be used as a backup method for DCs, you may only use AD aware backup methods; snapshots/imaging are not AD aware.
The usual recovery method would be to forcefully demote the "reverted" DC, clean out the AD of it, seize any FSMO roles the DC might have held, then repromote it back again; but I'm sorry to say that I have no idea how the Exchange Server on that machine will react to that.
More about this here:

Considerations when hosting Active Directory domain controller in virtual hosting environments
http://support.microsoft.com/kb/888794

Appendix A: Virtualized Domain Controllers and Replication Issues
http://technet.microsoft.com/en-us/library/dd348479(WS.10).aspx

How to detect and recover from a USN rollback in Windows Server 2003
http://support.microsoft.com/kb/875495