var
 SrcStream, DestStream: TStringStream;
 GZStream: TDecompressionStream;
 BytesRead: integer;
 MainBuffer: array[0..1023] of AnsiChar;
begin
 SrcStream := TStringStream.Create;
 DestStream := TStringStream.Create;
 try
   Address := 'http://www.wowprogress.com/export/ranks/eu_%D1%8F%D1%81%D0%B5%D0%BD%D0%B5%D0%B2%D1%8B%D0%B9-%D0%BB%D0%B5%D1%81_tier13.json.gz';
   Address := TIdURI.URLEncode(string(UTF8Encode(Address)));
   DM.IdHTTPconnect.Get(Address, SrcStream);
   SrcStream.Position := 0;
   GZStream := TDecompressionStream.Create(SrcStream);  [b]// Вот тут происходит AV по адресу 00000038[/b]
   try
     DestStream.Position := 0;
     GZStream.Position := 0;
     try
       repeat
        bytesread:=GZStream.Read(mainbuffer,SizeOf(MainBuffer));
        DestStream.Write(mainbuffer,bytesread);
       until bytesread < 1024;
     except
         GZStream.Free;
         exit;
     end;

function inflateInit2(var strm: z_stream; windowBits: TIdC_INT): TIdC_INT;
begin
 if not Assigned(strm.zalloc) then begin
   strm.zalloc := zlibAllocMem;
 end;
 if not Assigned(strm.zfree) then begin
   strm.zfree  := zlibFreeMem;
 end;
 Result := inflateInit2_(strm, windowBits, ZLIB_VERSION, SizeOf(z_stream));
end;

int ZEXPORT inflateInit2_(strm, windowBits, version, [b]stream_size[/b])
z_streamp strm;
int windowBits;
const char *version;
int stream_size;  // вот это как понимать?!
{
   int ret;
   struct inflate_state FAR *state;

   if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
       stream_size != (int)(sizeof(z_stream)))
       return Z_VERSION_ERROR;

  Address := TIdURI.URLEncode(string(UTF8Encode(Address)));

SrcStream := TStringStream.Create;

SrcStream := TMemoryStream.Create;

procedure Unpack(AStream: TStream);
 var
   UnzippedContent: TStream;
   Unzip: TIdCompressorZLib;
 begin
   AStream.Position := 0;
 
       Unzip := TIdCompressorZLib.Create(nil);
       try
         UnzippedContent := TMemoryStream.Create;
         try
           Unzip.DecompressGZipStream(AStream, UnzippedContent);
           UnzippedContent.Position := 0;
           AStream.Size := 0;
           AStream.CopyFrom(UnzippedContent, UnzippedContent.Size);
         finally
           UnzippedContent.Free;
         end;
       finally
         Unzip.Free;
       end;

 end;