Error: "Unescaped symbol at position..." on non-latin charsets

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Get JSON from 
http://maps.googleapis.com/maps/api/distancematrix/json?origins=Vancouver+BC|Sea
ttle&destinations=San+Francisco|Victoria+BC&mode=bicycling&language=ru-RU&sensor
=false
2. Parse then with JSON 
3. Get error "Unescaped symbol at position..."

What is the expected output? What do you see instead?
Need support for other charsets in "UnescapeString"

What version of the product are you using? On what operating system?
json-1.4. on WindowsXP SP3.

Please provide any additional information below.
Delphi unit code:
procedure TForm1.Button1Click(Sender: TObject);
var
  sl: TStringList;
  ja: TJSONarray;
  s: String;
  pac: PAnsiChar;
begin
  ja := nil;
  sl := TStringList.Create;
  try
    sl.LoadFromFile('json_ru');
    s := Utf8ToAnsi(sl.Text);
    pac := PAnsiChar(s);
    ja := ParseJSON(pac);
  finally
    if Assigned(ja) then
      ja.Free;
    sl.Free;
  end;
end;

Original issue reported on code.google.com by ruslan.p...@gmail.com on 26 Oct 2012 at 10:27