How to use Left 4 Dead skins in Garry's Mod?

I got a bunch of Left 4 Dead skins from the GAMEBANANA Left 4 Dead section and thought I can use them in Garry’s Mod. For example, Zoey. I’m trying to check out the different skins that I got, but they all look like this:

I just replace the files in the teenangst folder in materials/models/survivors. What am I doing wrong? How do I use Left 4 Dead skins in Garry’s Mod?

[editline]17th May 2014[/editline]

I also hope this is the right place to post. Google brought me to this section.

Seems that you’re using a pirated version of GMod right there.

I bought it. Should I ask my money back?

EDIT:
Also, skins work fine for all other Garry’s Mod characters.

[editline]17th May 2014[/editline]

Also, does anyone know how to use the Bodygroup Changer? I have this Elexis character that appears to have multiple skins and I can easily shift through them with the Bodygroup Changer. How would I go about this this with the Zoey character, for example?

You should update your Garry’s Mod; you’re using an old viewmodel which tells me you are using an outdated version.

Awh. Yes, I’ve been avoiding updates. So I haven’t been keeping up. I’ll try that, thanks.

How do you avoid updates? They’re automatic, have you left Garry’s Mod open for 3 years or just left Steam offline for 3 years? What the heck…

There’s an option in each game’s Steam properties to avoid updates. It’s been around for quite a while.