Hey sfbayarea:
If you would, keep us posted on what you find.
I have a Win7 64 bit desktop. When I installed WTLib 2016 it installed and ran fine. But I had the auto update turned off. When I tried the manual update it downloaded the 178 mb package without a hitch. Then it asked me if I wanted to do the update. I said yes and it started to update. But then it stopped and said it ran into an unexpected problem. After this WTLib would no longer run. I would try to start it and it would say that it ran into an unexpected problem.
So I uninstalled the program and tried to install from the DVD and the install stopped, saying there was an unexpected problem. I had to delete every Watchtower entry in the registry (with regedit) and then it would allow me to install again.