I have a template with many sections because much of the document needs to be
protected - in between the protected sections I have unprotected sections for
users to fill in text as they like.

If I fill in some text in one of the unprotected sections in the beginning
of the document, I suddenly finds that Word has inserted a page break in the
document after the section that was the last section on the page before I
filled in text.

I have seen this problem in Word 2000, but not in Word 2003.

Any ideas on what's happening?

I have checked all section definitions (all are Continuous) and I have
checked all paragraph formatting (clearing the Keep lines together, Keep with
next, and Page break before settings).