Why cant I get postprocess shaders to turn on through scripting?

[Gunrock]

I have spent countless hours trying to produce a script in which the player enters a room and activates this shader.

 

ACS:

script "SetShader" (int shaderSetting)
{
     //assuming that the player has a tid of 1000
    SetUserVariable(1000, "shaderSetting", shaderSetting);
}

Zscript:

class MyPlayerPawn : PlayerPawn
{
       int shaderSetting;
       int shaderSettingLast;
      
       override void Tick()
        {
              Super.Tick();
              if(shaderSetting != shaderSettingLast)
             { 
                  switch(shaderSetting)
                  {
                    case 0:
                     Shader.SetEnabled(player,"ShaderA",false);
                     Shader.SetEnabled(player,"ShaderB",false);
                    break;
	
                   case 1:
                   Shader.SetEnabled(player,"ShaderA",true);
                   Shader.SetEnabled(player,"ShaderB",false);
                  break;
	
                 case 2:
                Shader.SetEnabled(player,"ShaderA",false);
                   Shader.SetEnabled(player,"ShaderB",true);
                 break;
   }

                   shaderSettingLast = shaderSetting;
              }


         }
}

I included a demo map that I have been struggling with this script for hours on.

TestShader.zip