Hi Harry, Jim,
Haryy's video gave a hint to look at the opening profile from a different angle. The first two set of image shows face-based opening; the third and fourth vertical. As you can see vertical opening's profile is on xy-plane. Harry's code is probably defining lines on the face. That's probably the reason error message saying about sketch plane.
Harry, could you try setting z-value to the same value and try again? If it still does not work, then could you further hard code the definition of four profile lines? It will be easier to see if it is functional level error or usage issue.
Opening by face:
Vertical Opening. Notice the location of profile being on a floor level.
