They used a Sturdi wood floor that extended over the outriggers. The vacume bonded walls sat on the outside of this floor and was bolted through. The walls were connected with the vacume bonded roof. If the frame has been fixed the only logical conclusion is that one or more of the bolts holding the wall down have probably wallowed out and broken the base of the wall tubing that adjoins the two. They used a very thick aircraft grade aluminum that if this is the case you could probably send some lag bolts up from the bottom with adhesive and hopefully tie it down. The one I had for 16 years was not fixed to the frame as you are asking.
