How many sections are there? To me it seems as if you must have at
least three.
If you do have exactly three sections, I'd guess that the second one
have typed numbers ("Page 6"), repeated throughout the section. You
can easily fix this. Simply delete the text from the header (footer)
and then inserting actual page numbers via the Insert Page Number
button on the Header/Footer toolbar.
The other scenario is that "Page 6" represents actual page numbers.
But since a restarted page number requires a section break, then there
must be a new section for each of the "Page 6" pages. What you can
do is the following: For each section, set the page number format to
"Continue from previous section". This can be done via the Page Number
Format dialog box. You can access this dialog box via the Format Page
Number button on the Header/Footer toolbar. (Don't forget to make sure
that the final section, which starts numbering at 12, is also set to
continue its numbering from the previous section; otherwise page
numbering will be wrong again if you ever need to add pages before
it.)
For more, please see:
How to control the page numbering in a Word document
http://word.mvps.org/faqs/numbering/PageNumbering.htm
For more information about sections, see also:
Working with sections
http://word.mvps.org/faqs/formatting/WorkWithSections.htm