If you receive a message that your file errors when sending to print, please rasterise your file.
You can do this by opening the artwork in a design package, such as Photoshop, in CMYK mode at 445dpi.
Save as a tiff or high-quality jpeg (do this for both sides if your job is double-sided).
Finally, convert your tiff(s)/jpeg(s) back to a PDF using PDF/X-1a as your default setting.
