Ponoko problem

Every time I try to upload my ilustrater design onto ponoko it says this:

There is one or more elements in your .eps file that has a color. Rastering must be a solid fill that is a shade of grey. Check that your document is set up to use RGB colors and not CMYK. Please check and try again.

I don't know what to do. I even tried uploading it to photomake. I need help!