I was just looking at lesson 6, and the last example at the bottom did not show up. It said "Score Examples using JABB" and I got the box around something that appears when I try to use that sort of interactive object, but there was no play button or score.
Also when I went back to lesson 2, I got a message in the first 4 examples telling me that Internet Explorer cannot display the page. When I tried lesson 1, all the examples worked fine. All the other examples appear in lesson 6.