Dataset "" is not exists.

visiond

My report is ok in FR2.5, but when i migration fastreport from 2.5 to 3.09,i get the follow error: Dataset "" is not exists.

In my application, all data is created dynamic, for example, i always create a clientdateset, then load data from a xml file, then link the clientdataset to TfrxDBDataset, everything is ok in FR2.5, but when i migration fastreport from 2.5 to 3.09,i get the follow error: Dataset "" is not exists.

why??

The following code is test code, i can send the test project to anybody if you wish to get or download from the url: http://www.hsnet.cn/download/Fr309Test.exe

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procedure TForm1.Button1Click(Sender: TObject);
var
mast: TClientDataSet;
frmast: TfrxDBDataset;
report: TfrxReport;
begin
mast := TClientDataSet.Create(self);
mast.LoadFromFile('data.xml');
mast.Active := true;
frmast := TfrxDBDataSet.Create(self);
frmast.DataSet := mast;
report := TfrxReport.Create(self);
report.LoadFromFile('test.fr3');
report.ShowReport;
end;