What to do when found my emailid to be incorrect on the admit card of ibps po mt III 2013 that is scheduled on 10th november?

While filling up the applicatn form of the abov mentioned exam, my cousin unknowingly did a mistake in his emailid and was unaware of this mistke until he got his admit card. He says he had even checked the form before submittng. Will this create a problem in the future?How to make it right?