OCS 2007 R2 Group Chat Lookup Service fails to start

 Office Communications Server Group Chat Lookup Service fails to start and you see the following Event in the Event Viewer: Event Type: Error Event Source: OCS MGC Event Category: (1098) Event ID: 6381 Date: DATE Time: TIME User: N/A Computer: SERVERNAME Description: An error MGCLOOKU is stopping due to an unhandled exception has occurred due to an unhandled exception The certificate ‘CN=gcf.domain.com’ must have a private key that is capable of key exchange. The process must have access rights for the private key… Reset the permissions so the Lookup Service and Channel Service have full control to the C:\documents and settings\all users\application data\microsoft\crypto\RSA\MachineKeys folder and the files in the folder and restart the service