Portal 2 Big Blue Error.

[Username556]

I torrented Portal 2 a while ago and I played through the main game with no problems. However, I've run into a quite annoying issue. After beating the main game, I turned my attention to player-made maps posted on the Steam Workshop and downloaded by nefarious means. Some of these maps work just fine, but others are riddled with big, blue, flashing block letters reading "ERROR" in place of objects throughout the levels. These objects all function as they normally would, but it's really jarring to see so many big blue "ERROR" signs in place of cube-droppers and pressure plates. I looked online to see if I could find a solution to this, but all I could find was people saying to "verify game cache integrity" on Steam. Since I pirated, I clearly can't do that. I tried a bunch of different torrents to see if any of them had the missing files that result in the ERRORs, but it was use. Allow me to stress once again that I didn't ever encounter this problem when playing the main game. Do any of you know how to fix this? I suppose if one of you has a paid Steam version you could send me the files, but why would someone on the Pirate Bay Forum have a paid copy?... Here are some pictures: