I had a look through the source code of this program to see what generates that error. It seems to be related to RealSense's 'Face' module being missing, so 3DScan cannot find it.
May I ask if you are using the '2016 R3' RealSense SDK? If so, in that version, you need to install the Face Tracking module separately from the main 'Essentials' module.
If you are an R3 user, it would be a good idea to install the optional 3D Scan module too.
You can download the modules from a list of links at the bottom of this page: