Sorry, i did not make myself clear. I tried starting a new game. I could play, but the same error kept poping in the middle of the game every few seconds (freezing the game until you clicked the message away). That was a problem, but i still tried to keep going, but in the room 0, when i tried to access the computer to disable the lasers, the same message opened on full screen and that's when i could not progress any further.
I don't know what is causing this. c0face01_01b is face expression 01 (default), size 01 (smallest), b (blink). There is no reason it should not be accessible unless you messed with the files. Did you try to drag and drop over the previous version of the game, rather than extracting to a new folder entirely?
I thought i didn't, but i did not delete the older folder. I also noticed the files in both folders (0.4 and 0.6) did not have a png extension. Anyway, it seems i messed up, cause i just deleted everything (since saves don't work anyway), downloaded again, installed, and it's now working.
Thanks, keep it up, love this game.