I don't know on the problem, because it's been awhile since I watched this video. As far as when to do widgets and constraints, it's a matter of preference. With that said it's better to position the bones before adding constraints in my opinion. Some like the stretch to set parameters based on where the target bone/object is at. They can be reset pretty easily, but you have to remember that extra step if you apply constraints before positioning the bones.
Hi Grady,
From memory I think I was trying to save time having to create all the same constraints on the new bones.
But then I forget that the stretch-to was involved, so I had to fix those....In the end I did not save any time which I think I mentioned??
But yes, it's better to position the bones before the constraints. The widgets are just visual so mostly I do them last, but sometimes I do them earlier because it makes selecting things easier. But at the end of the day it's all your own preference.