动态创建的报表提示：未知的变量或数据库字段 ( 积分: 100 )

看看我的程序，我使用fastreport 3.09 ,大家帮我看看：
//---合计列
ReportSummary:= TFrxReportSummary.Create(Page);
ReportSummary.CreateUniqueName;
ReportSummary.Height :=17;

for i:=0 to ADOQuerymain.FieldCount-1 do
begin
Memo:=TfrxMemoView.Create(ReportSummary);
Memo.CreateUniqueName;
Memo.Left :=i*wdPer+65;
Memo.Width := wdPer ;
Memo.Text:= '[SUM(['+ADOQuerymain.Fields.DisplayName +'])]';
Memo.Font.Size := 8;
Memo.Height := 17;
Memo.Align := baleft;
Memo.VAlign:= vaCenter;
Memo.Frame.Typ := [ftLeft,ftRight,ftTop,ftBottom] ;
end;

看看我的程序，我使用fastreport 3.09 ,大家帮我看看：
//---合计列
ReportSummary:= TFrxReportSummary.Create(Page);
ReportSummary.CreateUniqueName;
ReportSummary.Height :=17;

for i:=0 to ADOQuerymain.FieldCount-1 do
begin
Memo:=TfrxMemoView.Create(ReportSummary);
Memo.CreateUniqueName;
Memo.Left :=i*wdPer+65;
Memo.Width := wdPer ;
Memo.Text:= '[SUM(['+ADOQuerymain.Fields.DisplayName +'])]';
Memo.Font.Size := 8;
Memo.Height := 17;
Memo.Align := baleft;
Memo.VAlign:= vaCenter;
Memo.Frame.Typ := [ftLeft,ftRight,ftTop,ftBottom] ;
end;