Oracle client problem with output parameter

cmd = new OracleCommand("<SP_NAME>", conn);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("USERNAME", OracleType.VarChar).Value = <username>;
            cmd.Parameters.Add("PASSWORD", OracleType.VarChar).Value = <password>;

            OracleParameter p1 = new OracleParameter("LOGIN_STATUS", OracleType.Number, 1);
            p1.Direction = ParameterDirection.Output;


            OracleParameter p2 = new OracleParameter("MESSAGE", OracleType.VarChar, 4000);
            p2.Direction = ParameterDirection.Output;


            OracleParameter p3 = new OracleParameter("SES_ID", OracleType.Char, 16);
            p3.Direction = ParameterDirection.Output;

            cmd.Parameters.Add(p1);
            cmd.Parameters.Add(p2);
            cmd.Parameters.Add(p3);

            OpenConnection();
            cmd.ExecuteNonQuery();

            string[] result = { "", "", "", "", "" };

            result[0] = cmd.Parameters["LOGIN_STATUS"].Value.ToString();
            result[1] = cmd.Parameters["MESSAGE"].Value.ToString();
            result[2] = cmd.Parameters["SES_ID"].Value.ToString();