Shader Not Blending Textures on Mobile

Hey all, I was just wondering if anyone had any idea why this shader doesn’t work for mobile. The specific line that has problems is : col = lerp(col, c, 0.5);

Whenever it is set to 0 or 1 it will work, however any values in between don’t seem to function properly and give me a pink terrain with the error “no subshaders can run on this graphics card”

I am attempting to write the shader for the Android platform at the moment. I haven’t ever really done shader programming, so I apologize if it looks horrid.

    Shader "Fog Of War/Terrain" {
    	Properties {
    		_FOWTex ("Detail", 2D) = "gray" {}
    		// Textures
    			_Control ("Control (RGBA)", 2D) = "white" {}
    		_Splat3 ("Layer 3 (A)", 2D) = "white" {}
    		_Splat2 ("Layer 2 (B)", 2D) = "white" {}
    		_Splat1 ("Layer 1 (G)", 2D) = "white" {}
    		_Splat0 ("Layer 0 (R)", 2D) = "white" {}
    	SubShader {
    		Tags { 
    				"Queue" = "Geometry-100"
    				"SplatCount" = "4"
    		#pragma surface surf Lambert
    		#pragma target 3.0
    		#include "UnityCG.cginc"
    		struct Input {
    			float2 uv_FOWTex;
    			float2 uv_Control : TEXCOORD0;
    			float2 uv_Splat0 : TEXCOORD1;
    			float2 uv_Splat1 : TEXCOORD2;
    			float2 uv_Splat2 : TEXCOORD3;
    			float2 uv_Splat3 : TEXCOORD4;
    		sampler2D _FOWTex;
    		sampler2D _Control;
    		sampler2D _Splat0,_Splat1,_Splat2,_Splat3;
    		void surf (Input IN, inout SurfaceOutput o) {
    			fixed4 splat_control = tex2D (_Control, IN.uv_Control).rgba;
    			float4 col;
    			float4 c;
    			col  = splat_control.r * tex2D (_Splat0, IN.uv_Splat0);
    			col += splat_control.g * tex2D (_Splat1, IN.uv_Splat1);
    			col += splat_control.b * tex2D (_Splat2, IN.uv_Splat2);
    			col += splat_control.a * tex2D (_Splat3, IN.uv_Splat3);
    			c	 = tex2D (_FOWTex, IN.uv_FOWTex).aaaa;
    			col = lerp(col, c, 0.5);
    			o.Albedo = col;
    			o.Alpha = 0.0;
    	Dependency "AddPassShader" = "MyShaders/Terrain/Editor/AddPass"
    	Dependency "BaseMapShader" = "MyShaders/Terrain/Editor/BaseMap"

I found that after modifying the above

#pragma surface surf Lambert

To :

#pragma surface surf Lambert decal:add decal:blend alpha

The script works properly.