小弟编了一个程序，在unit18（name:SplineTable)中加了DBGrid,table,DataSource等组件，在unit20里面调用了unit18.可是一编译，软件老是提示：undeclared identifier "splineTable"。当时无奈之下，我把unit18删了，然后重新建立一个Form,之后不再有这个错误提示，可是今天突然又出现了。请各位强人帮我看看到底是怎么回事。谢谢！程序附下：
unit Unit20;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Grids, DBGrids, DB, DBTables, TeEngine, Series,ExtCtrls,
TeeProcs, Chart, DbChart;

type
Tsplineposerrchart = class(TForm)
DBChart1: TDBChart;
Series1: TFastLineSeries;
Table1: TTable;
DataSource1: TDataSource;
GroupBox1: TGroupBox;
Label1: TLabel;
Label2: TLabel;
Edit1: TEdit;
Edit2: TEdit;
DBGrid1: TDBGrid;
Label3: TLabel;
DataSource2: TDataSource;
Table2: TTable;
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
SaveDialog1: TSaveDialog;
GroupBox2: TGroupBox;
Label4: TLabel;
Label5: TLabel;
Edit3: TEdit;
Edit4: TEdit;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure FormShow(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var

splineposerrchart: Tsplineposerrchart;

implementation

uses Unit18, Unit19;

{$R *.dfm}

procedure Tsplineposerrchart.Button1Click(Sender: TObject);
begin
splineposchart.show;
end;

procedure Tsplineposerrchart.Button2Click(Sender: TObject);
begin
splinetable.show;

end;

procedure Tsplineposerrchart.Button3Click(Sender: TObject);
begin
if savedialog1.Execute then
dbchart1.SaveToBitmapFile('d:\002.bmp')
end;

procedure Tsplineposerrchart.Button4Click(Sender: TObject);
begin
table1.Active:=false;
table1.TableName:='';
table2.Active:=false;
splineposerrchart.Close;

end;

procedure Tsplineposerrchart.FormShow(Sender: TObject);
begin
table1.Active:=false;
table1.TableName:=splinetable.table1.TableName;
table1.Active:=true;
edit2.Text:= splinetable.edit2.Text;
table2.active:=true;
end;

end.

unit18.splineposchart.show;