Article ID: 972091
You cannot join a conference call from Microsoft Office Outlook. Additionally, you receive the following error message in Microsoft Office Communicator 2007 R2:
Can't open the program because Office Communicator or Office Communications Server Attendant is already running on your windows user account. Please close the running program then try again
To resolve this issue, apply the following update: For more information, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/969695/ )Description of the update for the Communicator 2007 R2: July 2009
To work around this issue, restart the Office Communicator 2007 R2 process that is running.