What are the errors supposed to be?

I know on Left4Dead2 custom weapon files are often errors. You can pick them up and kill zombies with them until your teammates complain that you're lagging the game, but if you drop it the server crashes.
 
What are the errors supposed to be?

I know on Left4Dead2 custom weapon files are often errors. You can pick them up and kill zombies with them until your teammates complain that you're lagging the game, but if you drop it the server crashes.
Don't know, guess one of my Source games is corrupted, because I could play that map without problems last week.
 
Don't know, guess one of my Source games is corrupted, because I could play that map without problems last week.
My guess is when you converted the files from the games where those textures come from to SteamPipe, they became corrupted, giving you corrupted textures in Garry's Mod.

Just a guess, it may just be a game being buggy that requires a re-install.