I'm not quite sure how this happened, but I have accessed the same file on different computers. On one computer, which the file was originally created, the print preview for my report is just one page.
However, when accessing the same report with a different computer, the report's margins are changed, thus the same report takes up four pages.
I've gone to design view and tried changing the margins on Page Setup, but after assigning a new width for a specific side, the margin resets to the original value before I typed. I've also changed the default margin settings on Access Options, but this has no effect on the report.