It appears to be being held at the Faculdade de Letras da Universidade de Lisboa according to the Ed Media website here:
http://www.aace.org/conf/edmedia/
However, the two relevant pages on the University website do not show that conference at all:
http://www.fl.ul.pt/agenda/coloquios.html
http://www.fl.ul.pt/agenda/conferencias.html
Nearest metro: Cidade Universitaria - Metro Linha Amarelo (Yellow) - Direction Odivelas
Assuming that you are staying at the
HOTEL SOFITEL LISBOA
Av. da Liberdade 127
1269 Lisbon, Portugal
you would need to get the Metro Linha Azul (Blue Line) (direction Amadora Este) at Avenida Station. One stop along change at Marques de Pombal to Metro Linha Amarelo (Yellow) - Direction Odivelas. Get out at Cidade Universitaria station.