Both errors happened when Maria showed up. But I was able to continue through the game by simply pressing ignore, so it's probably something with less importance (maybe an image load).
What I find rough about the game is that there's not much to do, during the morning you go to Tohka's room, at night you sleep. And you only get 1 action per timeslot. It's good enough for now, but if this was a finished game it would be extremely boring.
I'm not sure what, but you should try to do something to avoid the feeling of repetitiveness. I don't know if you're planning to do more than just the main spirits, but it would be unbearably boring to just "go to X's room -> sleep -> go to Y's room -> sleep" over 10 times.