>Herewith..
What do you have for the page settings? Is it "Whole Page" or "Printable area."? If you're using Printable Area then generally it auto-adjusts according to the printer that is selected -- so sometimes what you see in the design area may be sometimes less and sometimes more than what's actually available. As a rule-of-thumb, allow for around 1/4" all around (so basically design your report so that you're using no more than 8" x 10.5" on a page). If you're using Full Page, then make sure you allow for 1/4" border all around. That means you'd probably want to make your page footer reflect that (i.e. it should be at least 1/4" tall).
Another thing to note -- nonprintable margins will vary from printer to printer, and has been stated by others, it's usually around 0.22" (sometimes less, sometimes more, and often not symmetrical).