On Wed, 30 May 2007, Sascha Schäfer wrote:
> I have a problem to read a special file with Jakarta POI. I can open
> this file in MS Excel. And Excel tells me, that this file is saved in
> the format of Excel 2003. But if I try to read this file with POI, it
> results to the error-message:
>
> “Invalid header signature; read 4503599627765769, expected
> -2226271756974174256”

This is an error that the underlying document isn't a valid OLE2 document.
Are you sure it's not in something like csv or html, with a .xls
extension? Excel tends to claim lots of formats are its own, even when
they're not.

I'd suggest trying to open the document in notepad, to check it's not
plain text. Also, try saving as in excel, and picking .xls, as that'll get
excel to convert it to a real ole2 document

Nick