[Unity Free]Add textures to existing Unity DOF Shader

Hello again,

I don't own Unity Pro, so the standard 'Depth of Field' option is not available to me. So I have set out to either finding a Shader online or making it myself, I have found a Shader in the Asset store made by Unity but it doesn't support textures so I tried to add that Property, but with no luck. Honestly I'm just really not sure what I'm doing.

Error Messages:

][1]

Original Code:

 Shader "Hidden/Render Depth" {
 SubShader {
     Tags { "RenderType"="Opaque" }
     Pass {
         Fog { Mode Off }
         
 CGPROGRAM
 #pragma vertex vert
 #pragma fragment frag
 #include "UnityCG.cginc"
 
 struct v2f {
     float4 pos : POSITION;
     #ifdef UNITY_MIGHT_NOT_HAVE_DEPTH_TEXTURE
     float2 depth : TEXCOORD0;
     #endif
 };
 
 v2f vert( appdata_base v ) {
     v2f o;
     o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
     UNITY_TRANSFER_DEPTH(o.depth);
     return o;
 }
 
 half4 frag(v2f i) : COLOR {
     UNITY_OUTPUT_DEPTH(i.depth);
 }
 
 ENDCG
 
     }
 }
 
 Fallback Off
 
 }
 

Modified Code:

     //============================================================================//
     //=========================Titel: 5_DOF-texture.shader========================//
     //===================Autor: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX===================//
     //==============================Datum: 03.04.2014=============================//
     //=================Beschreibung: Depth of Field-Texture Shader================//
     //============================================================================//
     
     Shader "Selfish Studio/5 - DOF Texture" {
         Properties { //Define any changeable properties here
         _Color ("Color Tint", Color) = (1.0,1.0,1.0,1.0)
         _MainTex ("Diffuse Texture", 2D) = "white" {}
         }
         SubShader { //Main Shader
             Pass {
                 Tags { "LightMode"="ForwardBase" }    
                 CGPROGRAM
                 #pragma vertex vert
                 #pragma fragment frag
                 #include "UnityCG.cginc"
                 
                 //User defined variables
                 uniform sampler2D _MainTex;
                 uniform float4 _MainTex_ST;
                 uniform float4 _Color;
                 
                 //Unity defined variables
                 uniform float4 _LightColor0;
     
                 //Base input structs
                 struct vertexInput{
                     float4 vertex : POSITION;
                     float3 normal : NORMAL;
                     float4 texcoord : TEXCOORD1;
                     #ifdef UNITY_MIGHT_NOT_HAVE_DEPTH_TEXTURE
                     float2 depth : TEXCOORD0;
                     #endif
                 };
                 struct vertexOutput{
                     float4 pos : SV_POSITION;
                     float4 tex : TEXCOORD1;
                     float4 posWorld : TEXCOORD2;
                     float3 normalDir : TEXCOORD3;
                 };
                 
                 //vertex function
                 vertexOutput vert(vertexInput v){
                     vertexOutput o;
                     
                     UNITY_TRANSFER_DEPTH(o.depth);
                     o.posWorld = mul(_Object2World, v.vertex);
                     o.normalDir = normalize( mul( float4( v.normal, 0.0 ), _World2Object ).xyz );
                     o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
                     o.tex = v.texcoord;
                         
                     return o;
                 
                 //fragment function
                 float4 frag(vertexOutput i) : COLOR
                 {
                     UNITY_OUTPUT_DEPTH(i.depth);
                     float3 normalDirection = i.normalDir;
                     float3 viewDirection = normalize( _WorldSpaceCameraPos.xyz - i.posWorld.xyz );
                     float3 lightDirection;
                     float atten;
                     
                     if(_WorldSpaceLightPos0.w == 0.0){
                         atten = 1.0;
                         lightDirection = normalize(_WorldSpaceLightPos0.xyz);
                     }
                     else{
                         float3 fragmentToLightSource = _WorldSpaceLightPos0.xyz - i.posWorld.xyz;
                         float distance = length(fragmentToLightSource);
                         atten = 1.0/distance;
                         lightDirection = normalize(fragmentToLightSource);
                     }
                     //Lighting
                     float3 diffuseReflection = atten * _LightColor0.xyz * saturate(dot(normalDirection, lightDirection));
                     float3 lightFinal = diffuseReflection + UNITY_LIGHTMODEL_AMBIENT.xyz;
                     
                     //Textures
                     float4 tex = tex2D(_MainTex, i.tex.xy * _MainTex_ST.xy + _MainTex_ST.zw);
                         
                     return float4(tex.xyz * lightFinal * _Color.xyz, 1.0 * i.depth);
                         
                 }
     
                 ENDCG
     
             }
         }
 
     Fallback "Diffuse"
 }

Thanks in Advance :D