Do you mean that the colors were "runny" in that they did not dry? Or do you mean that colors "bled" into one another as they dried? If the latter, chances are you used too much water to egg white or the overall icing was too loose to start, and it took too long to dry. As with any type of royal icing blend, you can get bleeding of colors if dark and light colors sit too long next to each other while wet. Usually, I work with my icing as thick as I can for the task at hand, and the colors set nice and fast without bleeding or fading.