Help with documentation.sln

I am trying to learn about MapWinGIS and would like to run the demo that is in the documentation directory “MapWinGIS-5.2.4\demo\MapWinGis Documentation.sln”

I have a copy of MapWinGIS.ocx registered and it looks good. However, the startup project “Interop.MapWinGIS” gives many errors (78) when I try to build or rebuild the project/solution. Most are along the lines of:

"The type or namespace name “IDrawingRectangle” does not exist in the namespace ‘MapWinGIS’ (are you missing an assembly reference?). The line in question from DrawRectangle.cs is: public class DrawingRectangle : MapWinGIS.IDrawingRectangle

I’m sure I’m missing an obvious reference in here, but I’m not familiar enough with the overall project to find what’s missing. Can anyone help get this solution to build so I can see a working copy? Thanks in advance.