Genie, I don't know about the original, but found this info in James J. Fuld, The Book of World-Famous Music, 4th ed. (Dover, 1995 p. 403):

"mw. Paul Burkhard. Published Nov. 17, 1948 [copyright records; LC], by Musikverlag und Bühnenvertrieb Zürich A.G., Zurich. Possible first edition: Front cover has a drawing of a master of ceremonies and is black and white. s. Der Schwarze Hecht. [...] Published on the same day was a booklet of four songs from the show, including O Mein Papa. The musical show was retitled Feuerwerk about Dec., 1950. Oh! My Pa-Pa, with English words by John Turner and Geoffrey Parsons, was published in 1953. Burkhard was born in Zurich in 1911 and was a conductor and composer in Switzerland. He died in 1977 in Zurich."

I think the show was "premiered in April, 1939"; sheet music was published later. Incidentally, there's a French version sung by Tino Rossi (Oh ! Mon Papa).

~Masato