Blank PDF created from Excel (with a twist)

I can create a PDF from Excel and read it in Acrobat myself no problem.

However, when I send the PDF file to others, the file opens, but the page is blank, or only has partial contents.

Have tested with PDFs generated from different XLS files, sent to different recipients, all with the same result. At my end, everything seems fine.

No similar problem with PDFs generated from any other file types, just XLS.

I'm using Win XP, Acrobat Pro 7.0.9, Office 2003. All patches applied.

The spreadsheets are simple, single page, text and numbers only, no graphics, macros or anything fancy.

I can find references to blank PDFs generated from Excel, but in those cases the creator experiences the problem. In my case, it looks fine to me, but others see the blank page. Offhand it would seem to be the recipient's problem, but it only occurs with PDFs created from XLS by me, and by several different people. They have no problem with other PDFs that I generate from different applications.

I'm a bit stumped by this one.
Thanks for any suggestions,
Tom