Make sure you set up the game_information {} section, especially the UUID:
Viewing post in Changes to save game format in new version of Adventuron
Some clues...
It is possible save only in the first 2 locations... You can LOAD from any other location if the SAVE was made in the first 2 locations. If you SAVE in any other location, the slot appears full, but when you LOAD from that slot, nothing happens... Very strange... My code has got something bad. I will continue with the investigations...