Seems that you're passing the method parameters to the class constructor.
This:
Object compObject = Activator.CreateInstance(runTimeDLLType, mthdInps);
Should be just:
Object compObject = Activator.CreateInstance(runTimeDLLType);
And then, you call the method with the parameters:
string mthdResult = (string)mthdInfo.Invoke(compObject, new object[] { objs });