Article ID: 978013
When you try to start a Meet Now meeting in Microsoft Communicator 2007 R2, the Live Meeting 2007 client does not connect to the MeetNow meeting. This problem occurs when your Live Meeting Service user ID exceeds 32 characters.
This problem occurs because the Meet Now meeting ID has a character limit of 32 characters. However, the user ID has a character limit of 64 characters. When a Meet Now meeting starts, the meeting ID is stored in the registry. However, the user ID is sent to the Live Meeting 2007 client as the Meet Now meeting ID. Therefore, if the user ID exceeds 32 characters, you experience the problem that is mentioned in the "Symptoms" section.
To fix this problem, apply the following update:
(http://support.microsoft.com/kb/976129/ )Description of the update for the Live Meeting Conferencing Add-in for Outlook: January 2010
To work around this problem, do not use a Live Meeting Service user ID that exceeds 32 characters.