hmm. ok I think I know what the problem is. I should have made a defualt appearance file for this mod as well.
The appearance.2da that is included with this mod is the one from Holowan plug-in and I made a few cosmetic changes to a few of the Characters and one of them is Nemo. What I did was give him one of Primes movie robes. SO here is how you can fix it either install Holowan Pug-in and then install This mod or you can Download Primes Movie robes and rename the white lightside robe and rename it to PMPI01.tga and nemo will be fine.
Or the last alternative is to extract one of the game jedirobe textures and rename it to PMPI01.tga. Sorry for the inconvienence I'll set up a non holowan plug-in version asap.
However if you only want to install the mask without the robe or npc you can do so by installing only these files :
I_Mask_075.mdl
I_Mask_075.mdx
revan.uti
ii_mask_075.tga
t7_revan02.tga
cheatcode is "giveitem revan"