求高手把这个验证码ocr.DLL Delphi调用代码声明部分转换成vb的。该如何处理

interface 
uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls; 
  type 
  TForm1 = class(TForm) 
    Button1: TButton; 
    Memo1: TMemo; 
    procedure Button1Click(Sender: TObject); 
  private 
    { Private declarations } 
  public 
    { Public declarations } 
  end; 
  var 
  Form1: TForm1; 
  procedure IMG2BMP(filename : PChar); Stdcall;external 'E:\down\advocr\AdvOCR.dll' name 'IMG2BMP'; 
  function OcrInit : boolean; Stdcall;external 'E:\down\advocr\AdvOCR.dll' name 'OcrInit'; 
  procedure OcrDone; Stdcall;external 'E:\down\advocr\AdvOCR.dll' name 'OcrDone'; 
  function OCR_C(OCR_type,filename : PChar): PChar; Stdcall;external 'E:\down\advocr\AdvOCR.dll' name 'OCR_C'; 
implementation 
{$R *.dfm} 
procedure TForm1.Button1Click(Sender: TObject); 
var 
a,b,c,d:string; 
begin 
a:='f:\q.jpg'; 
b:='f:\q.bmp'; 
c:='163_esales'; 
//  IMG2BMP(PChar(a)); 
        d:= StrPas(OCR_C('163_esales',PChar(b))); 
memo1.Text:='证码识别值:' d; 
  end; 
  end. 
  才学调用dll,这个IMG2BMP(PChar(a));好像能成功。而ocr_c就没反应了，我找了别人一源程序，反复看都差不多。别人的有效果。而我的不行，这是为什么?我这样弄是正确的吗？烦请指点，谢谢了~~~ 
贴子来源飞诺网(http://bbs.firnow.com) 详细出处参考：http://bbs.firnow.com/dview61t15478.html