GBA - Monster Rancher Advance 2

I have no idea if this is the right website for this, but I've been playing Monster Rancher Advance 2 for hours and hours on the Visual Boy Advance and I encountered a really serious issue that prevents me from progressing in the game.

For some reason a lot of things consistently make the game freeze.

When a Garu does this one claw attack the game always freezes. When I try to do Shoot training (Accuracy) the game always freezes. When I try to do Riddle training (Intelligence, Accuracy) the game always freezes.

I tried switching which monster I was training but the same things made the game freeze.

This is too much. A move is one thing (I could just save-scum until I managed to get through a battle without them using it) but an entire training type? That's way too limiting.

The other worry I have is that more and more things will make the game freeze. None of these things made the game freeze yesterday. I have no idea what's causing this.

It really sucks because I was just about to make my first monster into a Coach and it'd be a springboard for my next monster to be way better, but now I don't see the point.

GBA - Monster Rancher Advance 2 - Game-Breaking Bug