Other mistake: Riddler says that his "universal wax solvent" can eat through anything. Which begs the question, just what is that vat he cooks the stuff up in made of? We see the wax burn through solid steel vault doors. So it also ought to be eating through the vat, the floor and the bedrock, and sizzling its way down to the Earth's core.
Factual error: When Bruce, Dick, and Aunt Harriet are looking at the globe, Bruce corrects Dick's mistake about Lima being the capitol of Ecuador and says "No, as you can see, I was right. It's the capitol of Peru." and points to the globe to show him. Based on the position of Europe facing the camera, he's actually pointing to somewhere in northern Canada.