The Live Meeting add-in buttons do not appear in Outlook 2007
KB Article: https://support.microsoft.com/kb/944602
The Microsoft Office Live Meeting add-in buttons are not displayed in Outlook 2007. Or, you may receive the following error message in Outlook 2007 when you use Live Meeting 2005 add-ins or the Live Meeting 2007 console:
An error occurred while sending the e-mail invitation. Please check your email setting then send the invitation again.