The problem is that the map creator did not packed the map with the custom textures, instead they just added the content in the zip. Like i said before, if you want to see the map properly, just add the materials in -> tf\custom\snowpiercer\materials\scroll
But if you play the map in a server you did yourself, other people who join will have that issue, unless they put the materials too in that folder. The only way to fix that issue, as far as i know, is that the map creator updates the map and fixes that.