Toon Basic shader turns objects pink in 5.3.4f1

Hello I recently updated unity only to be presented with this: Everything was fine until I updated to unity 5.3.4f1 which I was using 5.2.2f1 until yesterday. Everything was fine until I switched scenes to update a script in it and now everything is pink in that scene even in the scene I was in before where everything was fine is now all pink. Also when I tried to re import it, all meshes that had materials with toon basic on flashed it's normal textures then turned pink again. I hope you can help me if you need to see the shader source here it is:

 Shader "Toon/Basic" {
     Properties {
         _Color ("Main Color", Color) = (.5,.5,.5,1)
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _ToonShade ("ToonShader Cubemap(RGB)", CUBE) = "" { }
     }
 
 
     SubShader {
         Tags { "RenderType"="Opaque" }
         Pass {
             Name "BASE"
             Cull Off
             
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             #pragma multi_compile_fog
 
             #include "UnityCG.cginc"
 
             sampler2D _MainTex;
             samplerCUBE _ToonShade;
             float4 _MainTex_ST;
             float4 _Color;
 
             struct appdata {
                 float4 vertex : POSITION;
                 float2 texcoord : TEXCOORD0;
                 float3 normal : NORMAL;
             };
             
             struct v2f {
                 float4 pos : SV_POSITION;
                 float2 texcoord : TEXCOORD0;
                 float3 cubenormal : TEXCOORD1;
                 UNITY_FOG_COORDS(2)
             };
 
             v2f vert (appdata v)
             {
                 v2f o;
                 o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
                 o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
                 o.cubenormal = mul (UNITY_MATRIX_MV, float4(v.normal,0));
                 UNITY_TRANSFER_FOG(o,o.pos);
                 return o;
             }
 
             fixed4 frag (v2f i) : SV_Target
             {
                 fixed4 col = _Color * tex2D(_MainTex, i.texcoord);
                 fixed4 cube = texCUBE(_ToonShade, i.cubenormal);
                 fixed4 c = fixed4(2.0f * cube.rgb * col.rgb, col.a);
                 UNITY_APPLY_FOG(i.fogCoord, c);
                 return c;
             }
             ENDCG            
         }
     } 
 
     Fallback "VertexLit"
 }