frustrationnn!

so i took my usb to get all my pdf's printed, all going good, until i get to my cover artwork. and it comes out with these random square shapes on them. so whipped out my laptop and had a look at my illustrator file, no stupid squares to be found. tried to print it again like 3 times, still these stupid squares. so efffff it. i hate illustrator and printing and saving to pdf's. screws up my life.