Just my opinion and experience- but I've never heard of kidney failure from breaking a fast. That doesn't mean it doesn't happen, but just that I've never heard of it.
Moreover, we're getting dangerously close to medical information here and I think if you are really concerned about the effects of what you ate on your kidneys you should consult a doctor - an M.D. - and not rely on Curezone.
I've only heard of two other people who broke their fasts like you did, but those two did not have any lasting problems. I am NOT recommending that anyone eat a big meal etc., but just trying to add another perspective.