Instead of inserting a manual page break before your heading, make the
heading paragraph 'page break before'. (If you always want to start a new
page on that weight of heading, put it in the style.) That way Word will
handle the page breaking correctly for you, which is much better than trying
to fix it by hand.

I think that should solve this problem (and prevent a few others), but you
may also want to uncheck the AutoFormat As You Type option that makes tabs
change numbering levels - in Word 2002 it's  'Set Left and First Indent with
Tabs and Backspaces'

You will probably also find it useful to read up how to manage outline
numbering safely in Shauna Kelly's detailed instructions:

http://www.shaunakelly.com/word/numbering/OutlineNumbering.html

Try adding a space and then tabbing - that stops the renumbering
(generally.)

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