谁能解释下“stream read error”错误

从网上下了个“小马哥远程控制”源码想学习一下，发现代码能编译，但生成服务端时出现“stream read error”错误：
procedure TForm1.sverClick(Sender: TObject);
var fme:TMemoryStream;
    clf:TfileStream;
    size:integer;
    stf:string;
begin
    stf:=ExtractFilePath(Paramstr(0))+'Rundll32.exe';
    if fileexists(stf) then deletefile(stf);    fme:=TMemoryStream.Create;
    clf:=Tfilestream.Create(application.ExeName,fmShareDenyNone);
    try
        clf.Seek(-sizeof(size),soFromEnd);
        clf.ReadBuffer(size,sizeof(size));
        clf.Seek(-size,soFromEnd);
        fme.CopyFrom(clf,size-sizeof(size));
        fme.SaveToFile(stf); //此处出错：stream read error!
    finally
        fme.Free;
        clf.Free;
    end;  form4.Visible :=true;
  FORM4.T1.Enabled :=TRUE;
  form1.Enabled :=false;
end;