Sometimes Shutterstock rejects some of my illustration with this message:
Color Profiles – Your image contains both RGB and CMYK color profiles. Please resubmit your vector with only 1 color profile.
The problem is that I used (during the drawing of this illustration) some CMYK color – maybe I took if from some swatch, or I used part of some other illustration, which was in CMYK mode. It is quite easy to convert illustration back to one – RGB – color mode.
Just open the illustration in Adobe Illustrator (tested in version CS3) and use
File / Document Color Mode / RGB Color save and reupload on the stock site