A family of Microsoft relational database management systems designed for ease of use.
In my particular case, I had originally installed a 64-bit version of Office on my 64-bit PC. Later, I uninstalled that version and installed the 32-bit version (for compatibility with other software). I don't know if that was the issue or if the installer is just messed up, but the path to the ACCWIZ directory was not in the list of trusted locations. What was there was:
C:\Program Files\Microsoft Office\Office14\ACCWIZ\
What I needed was:
C:\Program Files (x86)\Microsoft Office\Office14\ACCWIZ\
After adding the new path to the list of trusted locations and adding the Access Add-ins using the Add-in manager, all the Exernal Data Source wizards seem to be working.
Previous to this, I had tried a lot of things. I had tried renaming the wizards to xxx.old and having Access recreate them. I had even uninstalled and reinstalled Office 2010 a couple of times making sure to do the custom install to insure the wizards were installed. Still no joy. Only after fixing the trusted locations would the wizards work. Thanks to Kathy S. for the suggestion!