Sort crashes on Date columns

I have a grid with 4 columns of dates (out of a total of 58 columns) all in the format mm/dd/yyyy.  Whenever I attempt to sort, the program crashes with a message like Project prog.exe raised exception class EConvertError with message  ''09/03/200' is not a valid date and time.' Process stopped. 

Ignoring these columns is the only way to be able to sort.   Setting the style in

 procedure TGrid.AdvStringGrid1GetFormat(Sender: TObject; ACol: Integer;
  var AStyle: TSortStyle; var aPrefix, aSuffix: String);
begin
    case ACol of
    7,8,15,16 : Astyle := ssAlphabetic;
    end;

end;

does nothing.  I can set it's style as Alphabetic, Date, ShortDateUS, or even raw and I still get the invalid date and time message.

I cannot reproduce a problem here. A default grid initialized with:

It's very strange.  I have examined the date strings...no hidden characters or anything. Exports to Excel, CSV, and html all show normal dates.  (The error message I quoted should have read '09/03/2009' not '09/03/200' by the way.) 

The error takes me to the function TAdvStringGrid.CompareLine(Col,ARow1,ARow2: Integer): Integer;  in AdvGrid.pas to the line
                      res := Compare(Col,ARow1,ARow2,SortSettings.Direction);

Okay the problem is in the way the dates are read and parsed from the original delimited text files.  I still don't know what is wrong with the parsed string '09/03/2009' but the original string '20090903' works fine.  Oh the joys of updating someone else's old code...