[Solved] Missing textures

[Create]

Make sure you have Half Life 2 Episode 1 and Episode 2. If you do, make sure you have these games ticked in the little right hand corner of the Garry's Mod Menu. 

Spoiler :

Also be sure to have the map downloaded, as well as the two content packs that come with it;
Map
Content - Part 1
Content - Part 2

If this doesn't work, try making sure you have this setting;

Spoiler :

I hope this gets sorted soon!