This general advise has been given before, but I understand the concern about arriving in a county with ZERO currency just in case the the ATMs are down or my card won't work. I always save up some currency from the previous trip for just this purpose. But, on a first visit I'd just buy a small amount from the currency exchange at either the departing or arriving airport and not worry about the bad exchange rate - its going to suck no matter what you do. Then hit up the first ATM you find and get out the real money. Some airports have ATMs you can use before you even leave the baggage area solving the problem since you can still hit up the currency exchange window if the ATM fails, but I can't remember if FRA does or not. In any case, there is are several very convenient ATMs at FRA.