i always get this error when trying to buildcubemaps in the map. I compiled the 2fort map after adding a few brushes and it won't buildcubemaps. So, I extracted the skybox sky_tf2_04 and hdr to my materials\skybox folder, recompiled on hdr and it still wont build. Please help. What can I do? I've also tried mat_specular 0 before and after building. And I can't ignore it because it doesn't look right.