Help Request: I need help colorizing

Okay, so I've tried to colorize my tattoos and I'm still not having luck. I'm following the step-by-step instructions of this tutorial by CmarNYC and I'm using CmarNCY's Tattooinator utility. I'm using GIMP, as in the tutorial. 

But something isn't happening when I go to preview my tattoo presets in Tattooinator. First of all, it keeps showing the tattoos in black no matter what presets I use. And the tattoos show up in black in the game too, and they won't recolor in CAS. I have no idea what I'm doing wrong. I've gone over the tutorial several times. 

Anyone have any advice?