Avellino has no connection to Roseto Valfortore. Avellino is in the region of Campania, Roseto is in the region of Puglia. Here's some information from http://www.italyworldclub.com/campania/avellino/index.html:
Region Campania, Italy
The Province of Avellino has an area of 2,792 sq km, and a total population of about 430,000 inhabitants, and is administratively divided into 119 Municipalities. The province has a great environmental interest and is included in the Regional Parks Monti Picentini and Partenio, and comprises two WWF oases, Valle della Caccia in Senerchia and the area around the Ofanto dam in Conza della Campania.
Typical products are hazelnuts (one third of the whole Italian production), the chestnut of Montella, the renowned wines il Taurasi, Greco and Fiano, cherries, cheeses (as the caciocavallo of Montella, the black truffle of Bagnoli Irpino. Tourism is also a great resource, the main tourist destinations being the Sanctuaries of Montevergine (over 300,000 visitor per year) and of San Gerardo a Maiella, the archeological areas of Avella and Eclano, the Lancellotti castle, the early Christian Basilica in Prata.
You might want to check your geneology on the following website:
http://www.abruzzoforum.com/sitemap/avellino-8.htm
Good luck!