问题补充： 所有.dcu 文件都存在于同一个文件夹内，但delphi7 编译的时候总是提示
    [Fatal Error] MAIN.PAS(7): File not found: 'registerMember.dcu'
[Fatal Error] MAIN.PAS(7): File not found: 'registerMember.dcu'
[Fatal Error] MAIN.PAS(7): File not found: 'registerMember.dcu'

 急死我啦，请求高手出手相助。

感谢楼上的回答。
    registerMember 是我自己编写的单元名字。而且.dcu 文件也存在于同一个目录下，就是编译时候提示找不到。

感谢楼上的热心人相助，

program Mdiapp;

uses
  Forms,
  MAIN in 'MAIN.PAS' {MainForm},
  CHILDWIN in 'CHILDWIN.PAS' {MDIChild},
  about in 'about.pas' {AboutBox},
  registerMember in 'registerMember.pas' {frmRegisterMember},
  registerEmployee in 'registerEmployee.pas' {frmRegisterEmployee},
  registerArticle in 'registerArticle.pas' {frmRegisterArticle},
  transaction in 'transaction.pas' {frmTransaction},
  queryMember in 'queryMember.pas' {frmQueryMember},
  consumptionInfo in 'consumptionInfo.pas' {frmConsumptionInfo},
  queryEmployee in 'queryEmployee.pas' {frmQueryEmployee},
  changePwd in 'changePwd.pas' {frmChangePwd},
  registerCompany in 'registerCompany.pas' {frmRegisterCompany},
  authorization in 'authorization.pas' {frmAuthorization},
  logIn in 'logIn.pas' {frmLogIn},
  addUser in 'addUser.pas' {frmAddUser},
  addBalance in 'addBalance.pas' {frmAddBalance},
  addGoods in 'addGoods.pas' {frmAddGoods},
  dataModule in 'dataModule.pas' {dm: TDataModule},
  changeMember in 'changeMember.pas' {frmChangeMember},
  deleteMember in 'deleteMember.pas' {frmDeleteMember},
  consumptionSum in 'consumptionSum.pas' {frmConsumptionSum},
  queryBalance in 'queryBalance.pas' {frmQueryBalance},
  queryDeficiency in 'queryDeficiency.pas' {frmQueryDeficiency},
  changeEmployee in 'changeEmployee.pas' {frmChangeEmployee},
  deleteEmployee in 'deleteEmployee.pas' {frmDeleteEmployee},
  queryAchievement in 'queryAchievement.pas' {frmQueryArchievement},
  querySale in 'querySale.pas' {frmQuerySale},
  queryArticle in 'queryArticle.pas' {frmQueryArticle},
  changeGoods in 'changeGoods.pas' {frmChangeGoods},
  deleteGoods in 'deleteGoods.pas' {frmDeleteGoods};

unit MAIN;

interface

uses Windows, SysUtils, Classes, Graphics, Forms, Controls, Menus,
  StdCtrls, Dialogs, Buttons, Messages, ExtCtrls, ComCtrls, StdActns,
  ActnList, ToolWin, ImgList,logIn,registerMember,registerEmployee,
  registerArticle,transaction,queryMember,consumptionInfo,
  consumptionSum,queryBalance,queryDeficiency,queryEmployee,
  queryAchievement,queryArticle,querySale,changePwd,registerCompany,
  authorization,addBalance;
uses  后面的单元从registerMember开始都提示 file not  found ‘*.dcu’

感谢楼上朋友相助，不过错误依然。