*.xlsx is a ZIP archive containing XML and some other files. From your error message, the "Excel File" does not look like a ZIP file. That matches the file extension *.xls, so it most likely is an old-style Excel (95/97) file, a binary blob. If the old-style tools (Spreadsheet::ParseExcel) don't accept it, try opening a copy in a plaintext editor (Notepad++, Ultraedit, joe, vi, emacs, nano). There are a lot of people on this planet that call every file readable by any version of Excel an "Excel file", including CSV files. At least some Excel versions also accept CSV files with an *.xls extension, IIRC. So people rename *.csv files to *.xls and "it just works". If you see data that makes some sense in the editor, try using Text::CSV_XS.

Alexander