one could think the name is Donnerbauer, but interesting there also Donabauer to find. the name was then of germans in Bohemia.
present Austria has
29 hits for Donnerbauer:http://www.herold.at/en/telefonbuch/donnerbauer/
87 hits for Donabauer:http://www.herold.at/en/telefonbuch/donabauer/
phonebook Germany has 50 hits for Donnerbauer and 48 for Donabauer: http://www2.dastelefonbuch.de