Right, I've been through that post again about the Dynamic Friction lua. It is very confusing and nobody actually states what to do it in one simple post. It sort of develops as it goes along.
What I said in my original thread DOES appear to be correct and is working on my system. When Ben advised that FSUIPC had added an entry to the INI file automatically, I assumed it was the same one that I'd entered manually. It isn't, it's additional. It seems that if you want the lua to be activated automatically then an entry still has to be made manually. As I haven't the foggiest how to activate one any other way that's what I've done. All my aircraft show a marked improvement in ground handling. In the transition from stationary to wheels rolling and vice versa. Also lateral stability when taxying and on the take-off and landing runs. When steering (nose wheel or tail wheel) the aircraft responds accurately to my input with no oversteer or over-correction or weaving.
This video of the Mosquito rolling, taxying and taking off should illustrate what I mean.
http://youtu.be/eTDmTvRNLK0
So to recap what I've done:
Ensure you have FSUIPC4 v4.853.
Place the updated FSUIPC module v4.859m (FSUIPC4.dll dated 17/12/12) into the FSX/P3D Modules folder, replacing the older one.
Place the file DynamicFriction.lua into the FSX/P3D Modules folder.
Make the following entry manually into FSUIPC4.ini using notepad and SAVE.
[Auto]
1=Lua DynamicFriction
And that's it.
FYI FSUIPC will also add an additional entry into the ini file automatically.
[LuaFiles]
1=DynamicFriction
You need both entries.
Good Luck!
Ian
Off to add that entry in addition to the automatic FSUIPC created one. 
