Booleans and 3ds imports

I’m working on some tutorials from Bill Fleming’s 3D Photorealism Toolkit.He provides models in 3ds format from his website to follow along. I imported a couple of models to work on a remote, and his tutorial use boolean operations to get the desired result. However they don’t seem to be working as they should. My first difference operation subtracted the inactive object from the active object, and I’m sure it should be the other eay round. Then I tried to subtract another object, and only by using intersect instead of difference could I get the right result. Blend file is attached. I can use trial and error, but am wondering if there’s anything I can do to get the operations to work correctly.