Help! Can someone tell me why my Amana bottom freezer refrigerator is leaking water every so often from the bottom right corner? It's about 18 years old and there are no kids going in and out of it constantly. It has been well taken care of. I did notice this morning that the bottom floor under the basket has a large amount of ice. What could be causing this? I know about mixers and vacuum cleaners but nothing about refrigerators.