Removing the spectacles that conceal my super-secret Clark Kent identity, and hoping that nobody spotted that, I'll continue...

Having a quick shufti through the PP2012.mm1.txt that was included in the MatmaticDemos I noticed that IColor seemed to be used in the same sort of way that rgb was. Neither IColor nor rgb appear in the NodeReference.html. But since PP2012.mm1.txt compiled okay I thought it was worth a try.

Success

Here's the amended matmatic script below the line

# bagginsbill's matmatic script for a candle flame

# https://www.renderosity.com/forums/threads/2943991?page_number=2#msg4383217

# The compiler errors on the yellow = rgb line

# changed the 3 rgb references to IColor which is what the PP2012.mm1.txt seems to use, and that complied

AV = Bias(V, .25)

cy = .22

x = EdgeBlend(0, 1, .2) ** 2

y = (AV - cy) * .5

gy = 10

ygrad =  Clamp(1 - Abs(y * gy)) ** 2

blueopacity = Clamp(10 * x * ygrad)

py = Clamp(5 * Abs(AV - .3)) ** 2

px = (1 - EdgeBlend(1, 0, 2)) ** 2

darkpatch = 1 - Clamp((py + px) ** .5)

gy = Clamp((AV - cy) / (1 - cy))

gyp = (4 * gy * (1 - gy))**2

yellowopacity = Clamp(EdgeBlend(1, .3, 3) * Clamp(gyp - darkpatch))

yellow = IColor(255, 255, 200) 

orange = IColor(255, 200, 100) 

yellow = EdgeBlend(yellow, orange, 3)

blue = IColor(30, 30, 255)

yclr = HSV(yellow, 1, 1, yellowopacity)

bclr = HSV(blue, 1, 1, blueopacity)

clr = HSV(bclr + yclr, 1, 1, 5)

s = Surface(0, 0, 0, 0)

s.Alternate_Diffuse = clr

s.Transparency = .8

s.Transparency_Edge = 1

s.Transparency_Falloff = 1

I'll post the MT5 (or MC6) over on the Hivewire thread as I can't do that here.

The 3Dcheapskate (also available in DAZ and HiveWire3D flavours) occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.