What is causing this boundary-surface error?

I am trying to make a boundary surface following this youtube tutorial. Below I have attached a gif on imgur of me attempting to create the surface and what the surface is supposed to look like (from the video tutorial)

http://imgur.com/a/TCUyb

Tutorial does this step @ 27:20 .... https://youtu.be/lnJTfrqYfMU?t=27m17s

1 Answer

Its hard to say. I think it comes down to your selection for Direction 2. I can't read what the dialog box is saying in the animated image though.
.
I've attached a screenshot that shows it working. I think it is working anyway, I only watched a minute of so of the tutorial.

You can select the edge of the model, or 3DSketch1 and the results appear to be the same. Personally, I'd use a model edge over a 3D sketch, but it is just a personal preference. I seem to get the same result from both options.

I'd attach the file, but it work open in your educational seat if I save it outside of an educational seat.

When you are in the Boundary Surface tool, try right clicking directly on top of 3DSketch1 in the graphics window (not the feature tree). Use the "Select other" option to try picking different edges in that area. When sketches are over/under edges, it can be very tricky to pick the correct one.