I live in Switzerland but I've been many times in the places you mentioned to visit my relatives. (My parents are from Solopaca it's a little village near Frasso). Frascadore is indeed not a very common name in Italy either but nevertheless there are quite a few of them but I don't know any Frascatore. This makes me believe that maybe some transcription error occured when the first Frascadore's immigrated into the US.
The fact that I was not able to look-up any Frascatore in the Italian tel. directory confirms my theory. http://elenco.virgilio.it/http://elenco.virgilio.it/