I will have a fix for this problem soon. The crash reporter wants to fill out the e-mail address field from your address book (which is my own modification and fault not the crash reporter's original author). Now, when you haven't set a primary e-mail address in the address book, BetterZip crashes. You can either wait for the update later today or enter an e-mail address (fake is fine) in your address book. Sorry for the inconvenience.