Most likely because the pages are in different Sections. If you have the
non-printing characters displayed (¶) you'll be able to determine where the
Section Break occurs. Either remove the break or change the properties of
the page numbering in the following section to continue from previous.
This suggests that the document contains a section break. With the insertion
point in the second section, go to the Page Number Format dialog and choose
"Continue from previous section." Without knowing which version you have, I
can't be more specific about how to get to the dialog, but there's a Format
Page Numbers button on the Header and Footer toolbar in Word 2003 and
earlier.
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Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA http://word.mvps.org