Event ID : 8207
Category : General
Source : MSExchangeFBPublish
Type : Error
Message : Error updating public folder with free/busy information on virtual machine <Exchange2007ServerName> . The error number is 0×80004005

To resolve the situation do the following:

• Open the Exchange Management Shell
• Run the following command
  • get-publicfolder -Identity “\NON_IPM_SUBTREE\SCHEDULE+ FREE BUSY” -Recurse | fl name,Replicas
• Notice that at least one of the SCHEDUE+ FREE BUSY folders is missing an Exchange 2010 or Exchange 2007 server listed as a replica. For example, the output may appear as follows:
  • Name : EX:/o=contoso/ou=First Administrative Group Replicas : {}
• Run the following to add the Exchange 2007 server as replica for the folder
  • Set-publicfolder –identity “\NON_IPM_SUBTREE\SCHEDULE+ FREE BUSY\EX:/o=<netbios domain name>/ou=First Administrative Group” –Replicas “<exchange server>\Second Storage Group\Public Folder Database”
• Verify that the Exchange 2007 server is added as replica

Note All users whose free/busy data is not populated must accept or decline a meeting request to populate the free/busy data.

For more information see: http://support.microsoft.com/kb/945602

• For Public Folders
  • Get-publicfolder -recurse |fl name,replicas
• For System Folders
  • Get-public folder \non_ipm_subtree |fl name, replicas

To Move replicas to Exchange 2007

Moveallreplicas.ps1 –server<sourceserver> -newserver<destinationserver>

Note: Scripts are found at %SystemDrive%\Program Files\Microsoft\Exchange Server\Scripts. To run a script, type the following in the Exchange Management Shell:

[PS] C:\>cd $exscripts

[PS] C:\Program Files\Microsoft\Exchange Server\Scripts>.\Moveallreplicas.ps1

To add or remove a server from a public folder replica’s properties including subfolders you can use the following two scripts:
RemoveReplicaFromPFRecursive.ps1 –TopPubicFolder <\folder> –Server toRemove <servername>

AddReplicatoPFRecursive.ps1 –TopPulblicFolder <\folder> -ServerToAdd <servername>

For more information see this post: http://msexchangeteam.com/archive/2007/06/25/445429.aspx