for the more usual name Plattner you need a placename to start a research!
phonebook Austria - 846 hits:
Tyrol (489)
Carinthia (85)
Styria (58)
Vienna (53)
Upper Austria (52)
Lower Austria (47)
Vorarlberg (38)
Salzburg (23)
Burgenland (1)
http://www.herold.at/en/telefonbuch/tirol/plattner/212 hits in phonebook Italy:
http://www.infobel.com/en/world/teldir.aspx?ct=europe&co...South-Tyrol belonges since WW1 to Italy.
a Plattner-link with orgin for Plattner from South-Tyrol:
http://freepages.genealogy.rootsweb.ancestry.com/~heldenmut/http://freepages.genealogy.rootsweb.ancestry.com/~heldenmut/...