Hello, I have two ideas to solve your problem. I will only be focusing on your errors with the Experimental version (It’s much better than the stable one and requires little tricks to use it.)
The game raises errors when you download the AI, then try to move it from the cache folder (a place where rights are permissive user://cache) to /media/user/HDD/aidventure-experimental/models/LyaaaaaGames/distilgpt2/. It looks like it is on an external drive. So it’s probably just a permission problem. (Starting the game in admin (sudo mode) might work too but it’s not the best way)
You can either give more permissive rights on the AIdventure folder (just for the download part) or just move the game to your main drive.
Otherwise, (second option) you can let the server do the download for you (You will have little information about what happens, and I can’t guarantee success.) To do that, go in the game’s options and in the server tab. There, check ALLOW_MODEL_DOWNLOAD.
By reading the logs of the server, I understand the server doesn’t find the AI’s files.