Game freeze with FF1

I am playing FF1 on FCE Ultra. I have saved my game just outside the Ice Cave by using a house. When I enter the Ice Cave and take the stairway to the second floor of the cave, the screen turns blue and nothing else happens. That's it. It just turns blue. I've put in quite a few hours, and this is driving me nuts. Do you think it's the ROM, or a glitch in it, or what?

"If at first you don't succeed, destroy all evidence that you ever tried."