[Error] I can't load materials for vehicles, even if i write them in "download" line in vehicles.cfg. #31

So I installed your plugin for my TF2 Server. It worked very well. My friends told me to add more vehicles. I unzip addons from Garry's Mod and add to my server folder. Then write code for them. They work fine, but I can't load textures for them. I thought, what I missed the "material" line. But nope. I even put all materials to "download" line, but they just don't load. Please help me!
Here's my example code for vehicle:
"Sniper's Camper Van"
{
"name" "#Vehicle_CamperVan"
"model" "models/vehicles/camper.mdl"
"script" "scripts/vehicles/farcryhumvee_hl2.txt"
"type" "car_wheels"
"soundscript" ""
"key_hint" ""
"downloads"
{
"0" "models/vehicles/camper.dx80.vtx"
"1" "models/vehicles/camper.dx90.vtx"
"2" "models/vehicles/camper.mdl"
"3" "models/vehicles/camper.phy"
"4" "models/vehicles/camper.sw.vtx"
"5" "models/vehicles/camper.vvd"
"6" "materials/models/vehicles/camper.vmt"
"7" "materials/models/vehicles/camper.vtf"
"8" "materials/models/vehicles/camper_exp.vtf"
"9" "materials/models/vehicles/camper_normal.vtf"
"10" "materials/models/vehicles/citizen_body.vmt"
"11" "materials/models/vehicles/citizen_body.vtf"
"12" "materials/models/vehicles/citizen_head.vmt"
"13" "materials/models/vehicles/citizen_head.vtf"
"14" "materials/models/vehicles/details.vmt"
"15" "materials/models/vehicles/details.vtf"
"16" "materials/models/vehicles/interior.vmt"
"17" "materials/models/vehicles/interior.vtf"
"18" "materials/models/vehicles/interior_exp.vtf"
"19" "materials/models/vehicles/interior_normal.vtf"
"20" "materials/models/vehicles/body.vmt"
"21" "materials/models/vehicles/body.vtf"
"22" "materials/models/vehicles/body_exp.vtf"
"23" "materials/models/vehicles/body_height.vtf"
"24" "materials/models/vehicles/body_normal.vtf"
"25" "materials/models/vehicles/rear_sticker.vmt"
"26" "materials/models/vehicles/rear_sticker.vtf"
"27" "materials/models/vehicles/w_sniperrifle01.vmt"
"28" "materials/models/vehicles/w_sniperrifle01.vtf"
"29" "materials/models/vehicles/w_sniperrifle_normal.vtf"
"30" "materials/models/vehicles/weapon_lightwarp.vtf"
"31" "materials/models/vehicles/wheels.vmt"
"32" "materials/models/vehicles/wheels.vtf"
"33" "materials/models/vehicles/wheels_exp.vtf"
"34" "materials/models/vehicles/wheels_normal.vtf"
"35" "materials/models/vehicles/windshield.vmt"
"36" "materials/models/vehicles/windshield.vtf"
"37" "materials/models/vehicles/windshield_normal.vtf"
}
}