pdf images lose halftones in Pagemaker

I received a pdf file from a Graphic Artist with 2 graphics.  When I
place the PDF file in pagemaker and sent to my HP 5000 to print, it
won't print with Half Tones, the images are very detailed and they come

out very poor quality when printed to the HP 5000.  I also have an HP
4M and a HP 1200 and the files print out crisp and beautiful on these.
Unfortunately, I need this to print on the HP 5000 as I am trying to
create a plate to take to our inhouse printing press.

Any clues? 


Amy