Could not download your sample.
Do you have a drop shadow? Illustrator cannot understand blending modes (eg: multiply) from Photoshop, like Corel Draw can, so you may be seeing a halo around that. You ned to use the multiply in the tranparency palette to get that to work, and place a duplciate copy with no blending mode on top(that copy does nto have drop shadow).
The new link on own hostingn no account needed.
il post the ai file in about 10 hours
just transparent for the whole background, i hope you can see it in the pdf.
The effect is not visable in the illustrator artbord work enviremetn.
Wel visable in print, pdf, different pdf, print to pdf, save to adobe pdf.
gonne try tiff and some others to night.
@ MikeWenzloff : i used pdfx-1 due to printer request.
ill try 4 tonight
thx for your time