To uninstall, you have to first close the program. To do that: Right Click on the tray icon for Outlook on the Desktop (the small white icon with the day of the month on it in the bottom right corner of your screen) and click "Exit" You can then proceed with the uninstall from Add/Remove Programs.

This was a bug in Microsoft Outlook in the original release of Office 2010.  Installing SP1 of Office 2010 fixes the issue.  Please use windows update to get SP1.

This is due to a recent change Microsoft made in Outlook 2007 SP2 and Outlook 2010.  Microsoft has changed the shut down procedure for Outlook to ensure it shuts down in a more timely manner.  In the process, I believe they introduce a bug.   The outlook view control creates an instance of Outlook, but the instance shutdowns when open and then closing an item from the view control, even though the outlook view control itself is still running. 

One simple workaround that seems to work is to launch Outlook and leave it running before launching Outlook on the Desktop. I am in the process of trying to find a better workaround that doesn't require user intervention, but have not been successful yet.