In most cases, Acrobat prints correctly on the first try. If your printed labels are too low at the top and too high at the bottom, follow these steps.
The fix is a bit different on a Mac or on a PC.
When you go to print the PDF file of the labels, look for an option labeled "fit to page" or "shrink oversized pages to paper size," or "scale down large images to fit printed page."
(Or the equivalent; different systems say it differently.) When you find it, make sure the box is unchecked.
You may find this option on the first screen you see when you choose to print, or you may have to choose from a dropdown box on that main printing window. If the latter,
look for a choice like "Acrobat Reader," select it, then look for the checkbox. (On our Mac OS 9.2, it is under the dropdown "Acrobat Reader," and is called "fit to page"; but on our PC, it was right on the main print options screen. If you are using Mac OSX and its PDF viewer known as Preview, you'll find this option under the Preferences Menu, in the "Image" section.)
Bottom line... find that box and make sure it is unchecked. If that doesn't work, or if you can't find it, let us know.