I'm facing a problem, same as this (DPS App Builder Download Issue) but did not solve for me.
The App building process "works" for a Single Edition App, but then on the final screen nothing is listed under "Downloads." Under App Details it says : Activate App, App Type: Built-in Single Edition App. When you click Activate it gives this message: Activate your Single Edition app by purchasing a serial number from the Adobe Store.
What's going on?