Like others before me, I'm having troubles using the IdHttp(Indy 10.5.5) component in Delphi 2010. The code works fine in Delphi 7:

var
XMLString : AnsiString;
lService  : AnsiString;

ResponseStream: TMemoryStream;
InputStringList : TStringList;
begin
  ResponseStream := TMemoryStream.Create;
  InputStringList := TStringList.Create;

  XMLString :='<?xml version="1.0" encoding="ISO-8859-1"?> '+
          '<!DOCTYPE pnet_imessage_send PUBLIC "-//PeopleNet//pnet_imessage_send"   "http://open.peoplenetonline.com/dtd/pnet_imessage_send.dtd"> '+
          '<pnet_imessage_send> '+
          '   <cid>username</cid> '+
          '   <pw>password</pw> '+
          '   <vehicle_number>tr01</vehicle_number> '+
          '   <deliver>now</deliver> '+
          '   <action> '+
          '     <action_type>reply_with_freeform</action_type> '+
          '     <urgent_reply>yes</urgent_reply> '+
          '   </action> '+
          '   <freeform_message>Test Message Version 2</freeform_message> '+
          '</pnet_imessage_send> ';
  lService := 'imessage_send';

  InputStringList.Values['service'] := lService;
  InputStringList.Values['xml'] := XMLString;

  try
    IdHttp1.Request.Accept := '*/*';
    IdHttp1.Request.ContentType := 'text/XML';
    IdHTTP1.Post('http://open.peoplenetonline.com/scripts/open.dll', InputStringList, ResponseStream);
    ...
  finally
    ResponseStream.Free;
    InputStringList.Free;
   end;

The only differences so far between this and the D7 code is that I've changed the String types to AnsiString, and added the HTTP Request properties.

The response I get back from the server is 'XML failed to parse. Whitespace expected at Line:1 Position: 19', I'm assuming the XML got garbled up somewhere in the process, but I can't figure our where I'm going wrong.

Any ideas?