Some times when seinding seps to customers, It's easier to send in a DCS2 file that is saved as a eps. Depending on how they saved it with channel seps, all of te art could be hidden from view (but printable). Just hit print or go through your COLORs list to see what colors you have listed. That may tell you that it's reading other colors hidden below.
Then again, I just realized that it was saved as aPDF. so. Not sure, but could be the same thing.
Back to work.
D