我只建立了一个简单的MDI程序，在调用CHILD窗体时，就出现如下错误，烦请解答，谢谢！ (100分)

我只建立了一个简单的MDI程序，在调用CHILD窗体时，就出现如下错误，烦请解答，谢谢！

贴出你的程序.

unit TechMain;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ComCtrls, TFlatHintUnit, Menus, ImgList, ToolWin, jpeg, ExtCtrls,
MDIWallp;
type
TMain = class(TForm)
StatusBar1: TStatusBar;
FlatHint1: TFlatHint;
ImageList1: TImageList;
ToolBar1: TToolBar;
ToolButton1: TToolButton;
ToolButton2: TToolButton;
ToolButton3: TToolButton;
ToolButton4: TToolButton;
ToolButton5: TToolButton;
ToolButton6: TToolButton;
ToolButton7: TToolButton;
ToolButton8: TToolButton;
ToolButton9: TToolButton;
ToolButton10: TToolButton;
ToolButton11: TToolButton;
ToolButton12: TToolButton;
ToolButton13: TToolButton;
ToolButton14: TToolButton;
MainMenu1: TMainMenu;
Project1: TMenuItem;
CustomerManage1: TMenuItem;
N2: TMenuItem;
BusinessCard1: TMenuItem;
N3: TMenuItem;
Preview1: TMenuItem;
Print1: TMenuItem;
N6: TMenuItem;
Quit1: TMenuItem;
Edit1: TMenuItem;
Cut1: TMenuItem;
Paste1: TMenuItem;
Copy1: TMenuItem;
N4: TMenuItem;
Search1: TMenuItem;
Tool1: TMenuItem;
Calc1: TMenuItem;
N5: TMenuItem;
Notepad1: TMenuItem;
Window1: TMenuItem;
Tile1: TMenuItem;
Cascade1: TMenuItem;
ArrangeAll1: TMenuItem;
Help1: TMenuItem;
Help2: TMenuItem;
N1: TMenuItem;
About1: TMenuItem;
MDIWallpaper1: TMDIWallpaper;
procedure Quit1Click(Sender: TObject);
procedure Calc1Click(Sender: TObject);
procedure Notepad1Click(Sender: TObject);
procedure Cascade1Click(Sender: TObject);
procedure Tile1Click(Sender: TObject);
procedure ArrangeAll1Click(Sender: TObject);
procedure About1Click(Sender: TObject);
procedure BusinessCard1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Main: TMain;
implementation
{$R *.DFM}

uses ShellAPI,About,Card;
procedure TMain.Quit1Click(Sender: TObject);
begin
Close;
end;
procedure TMain.Calc1Click(Sender: TObject);
begin
ShellExecute(handle,'open','Calc.exe',nil,nil,SW_ShowNormal);
end;

procedure TMain.Notepad1Click(Sender: TObject);
begin
ShellExecute(handle,'open','Notepad.exe',nil,nil,SW_ShowNormal);
end;

procedure TMain.Cascade1Click(Sender: TObject);
begin
Cascade;
end;

procedure TMain.Tile1Click(Sender: TObject);
begin
Main.TileMode:=tbVertical;
Tile;
end;

procedure TMain.ArrangeAll1Click(Sender: TObject);
begin
ArrangeIcons;
end;

procedure TMain.About1Click(Sender: TObject);
begin
AboutBox.ShowModal;
end;

procedure TMain.BusinessCard1Click(Sender: TObject);
begin
BusCard.show;
end;

end.

这一大堆好象没涉及什么MDICHILD

最简单的方法：
在Delphi中，File --> New... --> Projects --> MDI Application
这样系统向导帮你建立一个简单的MDI程序，和你自己的比一比，就知道你的哪里错了

请说得明白一些，究竟你出现的是什么问题？

MDI问题多多！还是不要用了，微软对其中的bug都不解决了！

接受答案了.