If "Surface Modeler" is similar to other IMSI/Design plugins, you probably need to go through a "Start Up Options" dialog via the Windows "Start" menu. See if V19 is listed. If not, then Browse for the TCW19.EXE file, but it's doubtful that will work. They may need to update some Surface Modeler files so that it is recognized by V19.
V17—V21, 2015, 2016, 2017
Designer, Deluxe, Basic, Platinum
Windows 10, 64-bit