No numbers are printing even though it is in the print preview

[silvercats]

I added auto numbering to the by going to Insert>page numbers>bottom of the page.

It even showed in the print preview that numbers are there. but when I print it for real they are no there!
printed 20 documents,only about 12 had numbers on them.all of them had number on the print preview. this really messed things up for my project.

I noticed that if there is a big empty space at the bottom of the page like about 10 lines, numbers would print. if not,no. help!!

one person said that is because ,I keep pressing enter(that leaves empty lines on the paper) if I want to insert a new page to the document. but it shows on the print preview. Printer is OK