Material "uses unknown shader "vmt"" Issue

Many models are invisible on my server at the moment and I believe the errors below to be somehow related to this. It started after I updated one of my resource workshop addons (I didn’t even change the files below) and somehow this effected the materials. I think it began to happen after an update but I cannot pinpoint which one or a time. How can I resolve this issue? Thanks! :slight_smile:

Errors:

models/ffx/tidus/chains.vmt


"VertexLitGeneric"
{
	"$basetexture" "models/ffx/tidus/chains"
	"$halflambert" 1
}

models/code_gs/osama/mouth.vmt


"Teeth"
{
	"$basetexture" "models/Humans/Male/mouth"
	"$model" 1
	"$clientshader" "MouthShader"
	"$halflambert" 1
}


models/code_gs/osama/eyeball_r.vmt


"eyes"
{
	"$basetexture" "models\code_gs\osama\eyeball_r"
	"$iris" "models\code_gs\osama\pupil_r"
	"$halflambert" 1
	"$phong" "1"
	"$phongexponent" "10"
	"$phongboost"	"1"
	"$phongfresnelranges"	"[0.25 0.5 1]"
}