Missing Textures and Skybox in EvoCity

I just downloaded evocity for my server, and when I loaded the map, a few things happened that I don’t know how to fix.

Basically, the textures for the ground, billboards, and a few other things are gone, the skybox has completely disappeared, and a few models aren’t there (most noticeably the models used for the green and red lights on the street.)

So how do I fix this?

Do you have CS:S?
If not then there’s your problem.
Also does the server have CS:S on it?