You can look up by church records at this website:http://myweb.cableone.net/really/index.htm
scroll down to http://www.arkivalieronline.dk/
Be sure to print the simple how-to register instructions:http://myweb.cableone.net/really/arkiv-in.htm
Here you can find church and census records. You are looking for Nykobing Falster in Denmark.
I have a relative that lived there ~1905 by the name of Dorthea Hansen. She was married to Hans Peter Kreil. Let me know if we have a connection!