Weapon downloading problem

Excuse the noobish question, I just got Garry’s Mod today… but whenever I spawn a downloaded weapon (I tried the Tactical Weapons Pack first, then the Bang Bang You’re Dead gun to test if it was specific to that one pack), the skin turns into this black-and-purple checkered thing. Are the non-official weapons not compatible with the skin? Is this a common problem? Did I do something wrong or skip a step?

Thanks for the help.

Do you have CSS? because that might be causing the missing textures (purple, black textures)

Counter-Strike: Source? Sorry if I’m slow on this; my mind’s a little off today.

EDIT: Problem resolved, more or less. No, I don’t have the game. I see now that the textures are ported from what the game already has, so I shouldn’t have the texture for the gun if I don’t have the game that it comes from.

Everything else works fine, though. ^^