Every time when you use a Microsoft Office Live Meeting 2007 client to join a meeting that has Request e-mail address and company name enabled in Extended Registration on the Microsoft Office Live Meeting service, you must type your email address and company name.
To fix this problem, install the following cumulative update:
2029026 Description of the update package for the Windows-based Live Meeting 2007 client: July 2010
To work around this issue, open Options in Office Live Meeting 2007, type your email address in the E-mail box, type your company name in the Company box, and then click OK.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.