Hallo Richard:
Here are some ideas which you may have explored already. If you go to <
www.naila.de> you will find Stadt Naila and from there to the Stadt map.
Under Strasse "F" you will find Froschgruner Strasse. There is a Katholic
church on that street you many want to contact. Just northeast on the map
you will find Froschgrun.
I have been successful in writing to the Municipal Archives for genealogical
information. If you explore the Stadt Naila site you should be able to find
an address.
Also, this approach helps to supplement your German lessons.
Perhaps others on the Franken mailing list can help you in a more direct way.
Regards,
Ron Straube
Tewksbury, MA