Oh, I know. What a tricky situation.
From the first glance it looks like right click is not working but… After you click, you can’t download the image.
The thing is in your HTML markup. There’s an empty div overlayed over each image. So you can do the right click, because you don’t click on image but the div. If you remove the div to expose the image, you’ll see the code working.
So everything’s ok. I’d even say you have better image protection than can be achieved with the IW plugin :)