MSDN and TechNet Subscribers who installed Office Professional Plus 2010 or Visio Professional 2010 before May 1, 2010 may not have all product features enabled.
Last week when I logged on to the TechNet downloads website, I noticed that my orignal Office Professional Plus 2010 key had now become a “Terminal Service enablement” Key and there were now new keys for Office Professional Plus 2010, I did not think much of it until I read this article today http://support.microsoft.com/default.aspx/kb/983473?p=1
The product key you originally obtained from TechNet or MSDN is intended to enable Terminal Services capability. That product key enables installation and activation but does not enable all features. In order to use all of the functionality you must get the new product key that is now available. If you have existing installations of Office 2010 Pro Plus or Visio Professional 2010 with the original MSDN product key then you only need to configure the new key to activate the features. You can optionally use both product keys as needed but for new installations you should always use the new Office 2010 Pro Plus or Visio Professional 2010 key respectively.
It makes interesting reading because one of the things I was trying to do in Outlook 2010 was not working, changing my product key (full instructions in the KB) has now enabled this functionality.