idhttp提交数据出现http1.1/500异常

idhttp提交数据出现http1.1/500错误
在ie登录成功会跳转页面
抓包post后的数据如下:
HTTP/1.1 302 Found
Date: Sat, 17 Dec 2011 03:03:43 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
X-AspNet-Version: 2.0.50727
Location: http://www.ordroshop.cn/VipHome.aspx
Set-Cookie: ASP.NET_SessionId=d0bejn55ke5jou55vqao1u55; path=/; HttpOnly
Set-Cookie: j6ZJnpOJgJcqEuXCO5GZgzN0XF7eV%2Bl7=Id=YVnZLA8Oiaw=&Account=K2%2BUldK9l2YzdFxe3lfpew==&Type=aWrzlN6mAyI=; path=/
Cache-Control: private
Content-Type: text/html; charset=utf-8
Content-Length: 153

<html><head><title>Object moved</title></head><body>
<h2>Object moved to <a href="http://www.ordroshop.cn/VipHome.aspx">here</a>.</h2>
</body></html>

个人的程序如下
procedure TForm1.btnStartClick(Sender: TObject);
var
  F: TextFile;
  FileName: String;
  url: String;
  FeedBack: String;
  mStream: TMemoryStream;
  sData: String;
  Feedback: String;
  Data: TStrings;
  n, n1, n2: Integer;
begin
  FileName := FPath + 'temp.txt';
  url := 'http://www.ordroshop.cn/login.aspx';
  mStream := TMemoryStream.Create;
  FHttp := TIDHttp.Create(nil);
  FHttp.HandleRedirects := True;
  Feedback := FHttp.Get(url);
  FHttp.Get(url, mStream);
  mStream.SaveToFile(FileName);
  FreeAndNil(mStream);
  AssignFile(F, FileName);
  Reset(F);
  while Not Eof(F) do
  begin
  ReadLn(F, Data);
  Data := utf8toansi(data);
  n := pos('__VIEWSTATE', sData);
  if n > 0 then
  begin
  n1 := pos('value="', sdata);
  n2 := pos('" />', sdata);
  FViewState := copy(sdata, n1 + 7, n2 - n1 - 7);
  mminfo.Lines.Add(FViewState);
  end;
  n := pos('__EVENTVALIDATION', Data);
  if n > 0 then
  begin
  n1 := pos('value="', sdata);
  n2 := pos('" />', sdata);
  FViewState := copy(sdata, n1 + 7, n2 - n1 - 7);
  mminfo.Lines.Add(FViewState);
  break;
  end;
  end;
  CloseFile(F);
  //上面的程序为了得到__VIEWSTATE和__EVENTVALIDATION的值

  Data := TStringList.Create;
  Data.Add('__VIEWSTATE=' + FViewState);
  Data.Add('__EVENTVALIDATION=' + FEventValidation);
  Data.Add('=');
  Data.Add('txtAccount=ZXdgMwRX');
  Data.Add('txtPassword=DkEn9I866');
  Data.Add('LoginSubmit.x=54');
  Data.Add('LoginSubmit.y=22');
  Feedback := FHttp.Post('http://www.ordroshop.cn/login.aspx', data);
  mminfo.Lines.Add(Feedback);
end;

程序执行到FeedBack := FHttp.Post('http://www.ordroshop.cn/login.aspx', data);
出现project temp.exe raised exception class EIdHTTPProtocalException with message 'HTTP/1.1 500 Internal Server

请问各位老大帮忙看看

------解决方案--------------------
500 = 服务器遇到错误,无法完成请求。
------解决方案--------------------
在IDHTTP的OnRedirects事件中写转向的代码.!
------解决方案--------------------
出现了非法字符吧?