Downloaded SteamVR and my script gets "Render texture support and shader model 3.0 required" error

Its a script for volumetric lighting, it was working before, its from https://github.com/robertcupisz/LightShafts .
After getting steamVR and accepting all changes, my script gets an error of "Render texture support (including Rfloat and RGFloat) and shader model 3.0 required"