EvoCiity V33X Missing Textures + Errors

I tried installing many different content packs for the EvoCity V33X map, but I still have missing textures and errors. The missing textures so far are only in one building.

Why is it doing this?

Do you have HL2 EP1 & EP2 mounted?

You need cs:s, hl2 ep1, hl2 ep2 mounted,
a skybox script to make the skybox working,
some custom files for the lake / the fences of the houses nearby.