The latest version of Aspose.Excel (3.5.1) doesn't read Crystal 9 generated Excel files properly. In each case, the Excel.Worksheets.Count property returns 0 for the number of worksheets. I have attached a sample spreadsheet to this note.
Also, we have a very large 20mb XLS file that was created with Crystal 9 which Aspose.Excel is having trouble reading possibly for the same reason.
Mark M. Baker