Seem you have forgotten to skip existing File while installation or we have in ext4 no write Permissions in your Appdata.
That can maybe a Linux Permission Problem.
There are 3 possible Solutions for this :
1:
Simply edit the keeper.cfg in your Appdata keeperfiles and choose as Installation Directory simply d:
2:
press ctrl+alt+f and minimize the Window.
Start Thunar and copy the File /mnt/tmp/keeper/keeper.cfg into your keeperfiles Directoy.
3:
Delete your Entire Appdata Keeper Folder,restart the PND and after recreating the Appdata should the File keeper.cfg be in there.
Copy your Files into keeperfiles back,but dont overwrite keeper.cfg,simply skip this File
Please can you report if the keeper.cfg after first start is in your Appdata?
I hope Tapatalk write good because it forgot often the Return Key here.
When its real a Permission Problem on Ext4 then can you maybe not Save your Game,please report
I think the first Way is the easiest Way for your Problem what you have written