Hi Mike.

Make sure that the following lines  are correct:

[fltsim.XX]                                                    <- must be next consecutive number - i.e. [fltsim.14]
title=CS 767-300 Captain Paint14                  <- must be unique (not being used by another livery) - this is why I always use the PaintXX, where XX matches the fltsim.XX number
sim=B767-300RR                                          <- must be pointing to the correct AIR file (in this case the B767-300RR.AIR file)
model=rr5                                                    <- must be either ge5, ge3, pw5, pw3 or rr5
panel=
sound=RR                                                    <- must point to correct sounds (this won't affect the model showing up or not)
texture=qantasRR                                         <- must point to the texture.XXX livery textures folder (in this case the texture.qantasRR folder)
kb_checklists=
kb_reference=
atc_id=VH-OGQ
atc_airline=Qantas
atc_flight_number=763
atc_heavy=0
ui_manufacturer="Boeing"
ui_type="767-300 RR"
ui_variation=Qantas RR                                       <- used for identifying the livery
ui_typerole="Commercial Airliner"
ui_createdby="Captain Sim"
ui_wglts=1                                                   <- use this if you want the livery to have winglets. Either change to ui_wglts=0, or omit the entire line, if you don't want winglets
description="767-300 Base Pack v1.5\n(c) 2011 Captain Sim www.captainsim.com"

If all those are correct, the livery should show. Much of this (if not all) should be included in a "readme.txt" (or similar) file included with the file you downloaded.

Hope this helps.