I checked that file. There are some problems in. It refers to the old C-185 aircraft.cfg (the one before the update by Bernt Stolle)
So here's what to do:
You must have latest C-185F Tundra version:
//flight dynamics by B.Stolle Jan 2011
Use this in your aircraft.cfg
[fltsim.XX]
title=C185F SKYWAGON Tweto
sim=185_tundra
model=
panel=
sound=
texture=5
kb_checklists=C185_check
kb_reference=C185_ref
atc_id=N91361
ui_manufacturer=Carenado
ui_type=C185F
ui_variation=N91361 Tundra
ui_createdby=Carenado
ui_typerole=Highwing single Engine Prop
description=The C185, also known as the Skywagon, is a six-seat, single engined, general aviation light aircraft manufactured by Cessna. It first flew as a prototype in July 1960, with the first production model being completed in March 1961. The Cessna 185 is a high-winged aircraft with non-retractable conventional landing gear and a tailwheel. Over 4,400 were built with production ceasing in 1985.
atc_heavy=0
atc_airline=
atc_flight_number=
atc_id_color=0x00000000
atc_id_font=Verdana,-11,1,600,0
visual_damage=0
Replace XX with the correct following number in your aircraft.cfg
(example: if you have [fltsim.0] the next number is [fltsim.1] and so on.
-------------------------------------------------------------------
Now create a text file with the following content:
[fltsim]
fallback.1=..\texture
fallback.2=..\..\..\..\Scenery\Global\texture
fallback.3=..\..\..\..\..\..\Scenery\Global\texture
Rename it to:
texture.cfg
and copy it in folder /texture.5
Instead of doing this you can also use the one of the standard MS C-172.
See /C172/texture/texture.cfg
--------------------------------------------------------------------
In folder /texture.5
rename
thumbnail5.jpg
into
thumbnail.jpg
----------------------
Now it should work! Run FSX and choose your aircraft.
Dieter