How do I fix the missing textures (purple and black checkerboard) on my map?

http://img155.imageshack.us/img155/7452/gmmyhouse0002.jpg

I’m new to mapping, for some reason when I use env_cubemap, it still shows invalid textures.

Can someone tell me what to do, or link me to a tutorial?

Also don’t bitch on me not putting a light prop where the light is, i’m going to do that after i fix this problem.

do this in console;
mat_specular 0
buildcubemaps
mat_specular 1

You’re welcome.

Ah that works, thank you.
But will it work for people that download this map?

Yes. Its cubemaps. Every time you minimize your game or change resolutions and the game has to reload the materials that happens, its a source bug.