Load Case Combination

Hi..

I'm trying to use the GeometryGym plug-in "ggRhinoRobot" to perform a structural analysis model.

I want to define different load cases and different combinations of these load cases. But the "ggRobotCaseCombination" command is giving me trouble. It's not giving any output, and keeps giving a warning saying that it's missing input parameter for the "Load Combo Type". But whatever input I type in gives an error, whether it's an integer or a string.

Does anyone know what I'm doing wrong?

I have attached a simple example file, defining a number of beams and some load cases.