So there is no way to fix this?
You could post-process the exported file, using Applescript. Or export as XML, with a custom XSLT stylesheet*. Or convince your client to use a better application…
Thank you for your posts.
The answers provided by "comment" are correct (Thank you!). However, there may be a quicker solution.
With FileMaker Pro 7 on the Mac, when you export to a tab-separated or comma-separated text file and select the field order, look at the bottom of the dialog box under "Options". There is an option for "Output file character set", which normally defaults to Macintosh. Try either "Windows (ANSI) " or "ASCII (DOS) ". One of these file formats may work with Notebook.