Weapons not working when mapping

[Doomwaffle]

Hi. I can run TTT perfectly fine, with all weapons running fine. But when I try to place any weapon_zm or weapon_, an error shows up in Hammer and when I try to edit the entity's properties nothing shows up (only the angle is able to be edited...). Compiling and running map doesn't make anything show up. However, ttt_random_ammo and ttt_random_weapon do spawn usable weapons. Why can't I place individual weapons? I've tried refreshing content of SDK and multiple things. I had to point Hammer to ttt.fgd which I downloaded and put in a location not within any garrysmod folder, but that shouldn't be a problem seeing as though I can use all the other TTT entities. Any thoughts? Thanks in advance.