This cumulative update fixes the following issues:

• 976045 Error message when you try to add a contact to Outlook in Communicator 2007 R2: "Cannot connect to Microsoft Office Outlook to add a contact because Outlook is not responding"
• 976046 Hyperlinks are converted to lowercase if you send them in an instant message as text in Communicator 2007 R2
• 976048 Error message when you log off, restart, or shut down a computer that is running Communicator 2007 R2: "End Program - Communicator"
• 976050 When you answer an incoming call on a device that uses a simultaneous ring number, Office Communicator 2007 R2 generates a missed call notification
• 976051 The Communicator 2007 R2 screen freezes intermittently for several seconds when you are in an audio or a video conferencing session µ
• 976052 The display name of a contact is unresolved when you send a meeting request in Communicator 2007 R2
• 976054 Audio skips in Communicator 2007 R2 during Communicator calls or during Public Switched Telephone Network calls on a computer that is running Windows Vista

KB Article:
http://support.microsoft.com/kb/972884

Download:
http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=515d6dba-4c6a-48bb-a06a-d99c5742676d