In Microsoft Office Communicator 2007 R2, you right-click a contact and then click Schedule a Meeting. However, on the To line in Outlook, the display name of the recipient is unresolved. This makes the display name ambiguous and returns multiple matching entries. Therefore, if you select an incorrect recipient and you click Send in Outlook, the meeting request is sent to the incorrect recipient.
To resolve this issue, apply the following update:
972884 Description of the update for Communicator 2007 R2: Oct 2009
This update makes Communicator 2007 R2 give Outlook the Simple Mail Transfer Protocol (SMTP) address of the intended recipient. This fixes the problem because SMTP addresses are unique.