Sometimes, it's the little things.  Double check your aircraft.cfg.  I've lost count of how many times I've added a texture, then fired up the sim, and didn't see it, only to smack myself in the forhead because I forgot to change the [fltsim.XX] entry.  I DLed the texture and the aircraft, and edited the .cfg, and all was good.  Here's my .cfg...

[fltsim.]
title=Antonov AN-124 Global
sim=an124
model=
panel=
sound=
texture=Global
kb_checklists=
kb_reference=
description=The Anotonov-124 "Ruslan" has become one of the most famous cargo transporter worldwide for military and comercial transports (like parts of the european Ariane rocket). This paint scheme shows the design of the late eighties. Model and Textures by Tom Ruth. Modified defauld 747400 aircraft.cfg by Alexander Kvitta and Thomas Ruth. Copyright August 2003
ui_manufacturer=Antonov
ui_type=AN124
ui_variation=Global
ui_typerole=Heavy Freighter
ui_createdby=Tom
atc_heavy=1
atc_id=82078
atc_airline=Global
atc_parking_types=CARGO,MIL_CARGO,RAMP
atc_flight_number=8278

Change the "2" to the appropriate number, if you have more textures than the original DL package.

Hope that helps!

No problem!