If you've received this error message, that means your file has not been exported correctly.
Below we point you to the key things you need to do when exporting from each of our supported software packages:
When saving your file as an ‘Illustrator 8 EPS’, check that your screen matches the panel below (with all of the boxes under ‘Options’ remaining unticked). The most important one which is causing you trouble now is "Include CMYK Postscript in RGB Files".
Once you've resaved in this fashion, your file should upload correctly.
If you are using any version of CorelDRAW previous to X6, you MUST export your file as a SVG. You can read more about that in our CorelDRAW starter kit.