Let me save someone some time. So I was trying to run SharePoint Products and Technology Configuration Wizard for MOSS 2007, and during the course, I faced the error message, as seen from the screen dump above, "One or more types failed to load. Please refer to the upgrade log for more details". After alot of research, I came to learn that this was being caused by Office 2010 which was installed on the same machine as MOSS 2007. Therefore, the error went when I uninstalled Office 2010. Happy holidays ;)
Data and Advanced Analytics. Formerly SharePoint.