That one is easy: JSONObject constructor taking a string expects a JSON string which always starts with { and ends with }. You'll have to wrap your array into { and } like this for instance:
string jsonString("{ "myArray" : [{"name":"Sergio Seiji de Souza Shimose"},{"name":"Marcelo Camargo"},...]}");
JSONObject jo = new JSONObject(jsonString);
[Edit]
JSONArray array = new JSONArray(jsonString);
[/Edit]
Cheers!
—MRB