On the top of the page you must fill the fields "Agencia" and "Conta" (fill all fields with zeros), if you click on the OK button you get "Informações inválidas." wich means Invalid Information, but if you hit ENTER instead clicking you get "Todos os campos Agencia, Conta e Digito devem ser preenchidos!" which means "All the fields must be filled".
Confirmed with r36009. It works as expected in Firefox 3. I am not quite sure what is causing this behaviour.