Why does my shader make geometry disappear when scene reloads?

I created a new shader that uses vertex color alpha, a tint color, and a single alpha texture. I can assign this shader to my object, and it behaves just like I want it to. Then, I save my scene, exit Unity, relaunch Unity. Now any object assigned to this shader appears completely transparent.

I know it hasn't moved, because I can select it and see its wireframe. If I assign a different shader to the material, I can see the object again. I then assigning my custom shader again and it looks fine. But, if I exit Unity and restart, everything is gone again.

Here is the code for my shader. I'm wondering if turning lighting off has something to do with it?

------ See shader below --------

Shader "My Shaders/Alpha Vertex Alpha" {

Properties 
{
    _Color ("Color Tint", Color) = (1,1,1,1)
    _MainTex ("SelfIllum Color (RGB) Alpha (A)", 2D) = "white"
}
Category 
{
    Lighting Off
    ZWrite Off
    Cull Back
    Blend SrcAlpha OneMinusSrcAlpha
    Tags 
    {
        Queue=Transparent
    }
    BindChannels
    {
        Bind "Color", Color             // bind vertex color to 'primary' color
    }
    SubShader 
    {
        Pass 
        {
            SetTexture [_MainTex] 
            {
                constantColor[_Color]
                Combine Texture * constant, Texture * Primary
            }
        }
    } 
}
FallBack "Transparent/Diffuse"

}