I've had a similar problem sometimes in the print preview, and usually I have to find a way to tell it to print Landscape and not Portrait. If you've been looking through all the settings though, I wonder if that isn't an option, or maybe it still isn't working for some reason, in which case I'm not entirely sure! Another option could be to try to go through a different program--like if you're opening the PDF up in the browser, maybe try a different browser, or a PDF reader program like Acrobat. Sometimes they'll have different printer settings in each program.