Placing swedll32.dll in a web application

I need to create a solution for a client of a web application that produces calculations of the position of the planets.

I was told to use this swedll32.dll library, and I did some testing and it works great in Delphi 7.

The problem is that I need to publish to a web application and I'm not getting it to work. I tried using .NET

What solution do I need:

• A web application (any language) that accesses this dll and does the calculations

• A hosting option for this application

For more details on the application follow links to sample codes and documentation.

link

link

I'll put a very simple delphi code snippet to understand what I need.

Very grateful =)

function swe_julday(year     : integer;
                    month      : integer;
                    day        : integer;
                    hour       : double;
                    gregflag   : integer
) : double; stdcall; far; external 'swedll32.dll' name '_swe_julday@24';

function swe_calc(tjd          : double;    {Julian day number}
                   ipl         : Integer;   {planet number}
                   iflag       : Longint;   {flag bits}
                   var xx      : double;    {first of 6 doubles}
                   sErr        : PChar      {Error-String}
): Longint; stdcall; far; external 'swedll32.dll' name '_swe_calc@24';


function PegaPosicaoDoPlaneta() : string;
var
  tjd,
  dhour,
  tjdet : double;

  planet_number : integer

  iday, imonth, iyear : integer;
  iflag, rflag : Longint;
  xx    : Array[0..5] of double;
  serr :  Array[0..255] of Char;
  sjul: String[30];

  resultado : string;
begin

  iday := 1;
  imonth := 1;
  iyear := 2016;

  ihour := 11;
  imin := 59;
  isec := 00;
  dhour := ihour + imin / 60.0 + isec / 3600.0;

  tjd := swe_julday(iyear, imonth, iday, dhour, 1);

  planet_number := 0;

  iflag := 0;
  rflag := swe_calc(tjd, planet_number, iflag, xx[0], serr);

  Str(xx[0]:16:10,  sjul);

  resultado := 'Planeta ' +  IntToStr(planet_number) + ' na posicao = ' +  sjul;
  result := resultado;
end;