Sorry for the late reply (itch.io forgot to send me notifications for quite a while, it seems).
I can't reproduce this in my testing. In your case, it seems as if the game doesn't change the variable properly ("fotogramma 0" doesn't exist, because it should always start with "fotogramma 1" and go up from there) but there are no obvious reasons as to why this should happen.
Is it completely random? Do you remember any of the events that triggered the bug (in case I want to dig a bit deeper)?
any event that did the black and white spiral hypnosis. I purposely tried some multiple times and every single one at some point would give me this exact error. it most frequently occured with the anxiety cure (not sure if thats what it is called but it is the event where mc tells the hypno guy she has a problem with, for example, her sexuality) hypnosis at the cirkus. The standard hypno training gave it to me less frequent. Though, I wonder if it could be related to my drives read speed suddenly being a lot slower than it used to be?
Glad to know it seems to be working fine now, at least. Since the animation basically just switches quickly between the various frames and then cycles back at the end, perhaps a faulty drive can't keep up with having to access a different file every frame, and that causes timing issues or something (perhaps because of how RPG Maker handles images). I am just speculating, however. This is an old engine, and it doesn't use the GPU much (if at all), making it harder to compare with modern games.
