My suggestion is to take your entire document of approx 350 pages and
save it as a STRAIGHT-TEXT file with not a solitary piece of
formatting or layout included and create your html pages from that
text. (It's the only was to avoid such simple errors as you currently
face.)

This also works:
* Open your document in Word.
* Copy everything to the clipboard: CTRL+A CTRL+C
* Open Dreamweaver (I don't know Frontpage, never used it)
* Paste from clipboard: CTRL+V

This method preserves most of the formatting AND gives you better HTML.
Dreamweaver 2004 is even supposed to be HTML 4.01 and XHTML compliant.

I've been told this method also works for FrontPage. However, pasting 10
pages in DW caused a pause for me while it showed up--the OP might want to
do this in chunks.