A family of Microsoft word processing software products for creating web, email, and print documents.
First, you do not need those options. They are, IMO, crutches.
However, as Suzanne said, this message means your Built-In-Building Blocks.dotx file is damaged.
In any version of Word starting with Word 2010, you can delete it and Word will build a new one for you. You want to do this even if you do not need these page number building blocks. (In Word 2007, the file is the Building Blocks.dotx file and you would want to rename the file.) The reason you want to rebuild this file even if you don't really need the page number building blocks is because this has all the building blocks supplied such as stock Tables of Contents, Cover Pages and Quick Tables.
For more, see my page on this problem: Page numbering / header / footer problems Word 2007 - Word 2024! (365).
It gives locations and instructions.
If you go to the header or footer where you want a page number, you can press Shift+Alt+P to insert a page number field. It can be added in other ways as well and formatted as you would anything else.
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