OotD crashes on startup. What's wrong?

There is no one definitive answer for this. In most cases it is caused by an incorrect or partially corrupt installation of Microsoft Office. Doing a complete uninstall and reinstall of Office usually fixes it. In other cases, it's simply a case of a dll that was not registered correctly during installation. This has worked for some people: http://support.microsoft.com/kb/870707.

Alternatively, you can also try using an older version (which uses a different mechanism to connect to Outlook).