It shows a Vdd of 5V on the datasheet. Vdd tells you its cmos. So about 1/3 and 2/3 vdd are most likely where your logic thresholds lie. I'd assume that that the LED Vdd and your system need to be about the same else you need a level shifter. [They eat 60mA each (R+G+B all on). 1mA all off. Allegedly] Check your rails aren't sagging or boucning during logic tranistions. Look at you local decoupling scheme. You probably need 100n right at the LED leads.